Design method for cooling water seam structure of large-section special-shaped blank crystal copper plate

Abstract

The invention provides a design method for a cooling water seam structure of a large-section special-shaped blank crystal copper plate. Comprising the following steps: establishing a three-dimensional flow heat transfer coupling model of molten steel in a special-shaped blank crystallizer, and calculating a temperature field and solidified blank shell distribution in the crystallizer under the condition of considering molten steel flow; determining the cooling strength required by each area in the circumferential direction, and completing the preliminary design of the cooling water seam structure of the copper plate; establishing a copper plate-molten steel-cooling water three-dimensional flow heat transfer coupling model of the large-section special-shaped blank crystallizer, and calculating to obtain molten steel flow heat transfer characteristics in the crystallizer under the condition of considering a cooling water seam structure of the crystallizer; according to the difference between a simulation result and a production demand standard, determining an adjustment strategy of the cooling strength of each area on the surface of the casting blank, and optimizing a copper plate cooling water seam; and the optimal copper plate cooling water seam structure meeting the production requirements is obtained. The problem of unreasonable structural design of the cooling water seam of the current large-section special-shaped blank crystallizer copper plate can be solved, the quality of a large-section special-shaped blank product is remarkably improved, and the service life of the crystallizer copper plate is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of steelmaking and continuous casting, and in particular to a method for designing a cooling water seam structure of a large-section special-shaped blank crystallized copper plate. Background Art

[0002] Compared with traditional cross-section billets, profiled billets have more boundary changes, including eight convex corners, four concave corners, and twelve independent straight line segments. Its special molten pool shape and more corner areas make the flow pattern of molten steel in the crystallizer complex, and the cooling conditions on the surface of the solidified billet shell are less uniform. If the design of the cooling water seam structure of the crystallizer copper plate is unreasonable, the cooling uniformity of the surface of the solidified billet shell will be further deteriorated, which will eventually lead to uneven internal structure of the billet and easily cause crack defects. In addition, the unreasonable cooling water seam structure of the copper plate will also significantly affect the peak temperature and uniformity of the hot surface temperature of the copper plate, resulting in a significant reduction in the service life of the copper plate. Therefore, the design of the cooling water seam structure of the crystallizer copper plate is an important part of the development of profiled billet crystallizers.

[0003] At present, the design of cooling water seams for copper plates of profiled billets is usually based on field tests or numerical simulations. The field test method is costly and has a high risk of steel leakage. Numerical simulation has a lower test cost and can avoid the risk of steel leakage in field tests. The flow of molten steel in small-section profiled billets has little effect on the heat transfer process. Existing studies only use heat transfer models to calculate the cooling and solidification behavior of the billet under different cooling water seam structure designs. However, affected by the submerged nozzle, the forced flow of molten steel in the crystallizer will significantly affect the temperature distribution inside the billet, and there are significant differences in the solidification process of molten steel under different submerged nozzle structures. This difference is particularly significant in the crystallizer of large-section profiled billets. Only by considering the heat transfer process can the cooling and solidification process of molten steel in the crystallizer of large-section profiled billets be accurately simulated. Comprehensively considering the flow and heat transfer behavior of molten steel in the crystallizer of large-section profiled billets, that is, considering the influence of the submerged nozzle structure in the process of establishing the heat transfer model, can provide an accurate basis for the design of the cooling water seam structure of copper plates of large-section profiled billets. Summary of the invention

[0004] The purpose of the invention is to provide a method for designing the cooling water seam structure of a large-section special-shaped blank crystal copper plate.

[0005] The present invention is achieved through the following technical solutions:

[0006] The present invention relates to a method for designing a cooling water seam structure of a large-section profiled blank crystallized copper plate, comprising the following steps:

[0007] Step 1, establishing a three-dimensional flow and heat transfer coupling model of molten steel in a profiled blank crystallizer, and calculating the temperature field in the crystallizer and the distribution of the solidified blank shell under the consideration of the flow of molten steel;

[0008] Step 2, determine the cooling intensity required for each circumferential area and complete the preliminary design of the copper plate cooling water seam structure;

[0009] Step 3: Establish a three-dimensional flow and heat transfer coupling model of copper plate-molten steel-cooling water in a large-section profiled blank crystallizer based on the cooling structure design, and calculate the flow and heat transfer characteristics of the molten steel in the crystallizer considering the cooling water seam structure of the crystallizer;

[0010] Step 4: According to the difference between the simulation results and the production demand standards, the adjustment strategy of the cooling intensity of each area on the surface of the ingot is determined, and the cooling water gap of the copper plate is optimized;

[0011] Step 5, repeating the copper plate-molten steel-cooling water flow heat transfer coupling model calculation and cooling water seam structure optimization;

[0012] Step 6, finally obtaining the optimal copper plate cooling water seam structure in which the temperature of the ingot and the thickness distribution of the ingot shell under the action of the molten steel of the specific immersion nozzle structure meet the production requirements.

[0013] Preferably, in step 1, the three-dimensional flow and heat transfer coupling model of molten steel in the profiled billet crystallizer includes: a geometric model and a corresponding flow and heat transfer calculation model.

[0014] Preferably, the three-dimensional flow and heat transfer coupling model of the molten steel in the profiled billet crystallizer includes: a turbulence model of the molten steel in the crystallizer, a molten steel heat transfer model, and a molten steel solidification model.

[0015] Preferably, in step 1, the specific steps of establishing the three-dimensional flow and heat transfer coupling model of molten steel in the special-shaped billet crystallizer are: (1) meshing the geometric model and setting the material properties and process parameters of the steel grade; (2) setting boundary conditions for the flow and heat transfer model according to the submerged nozzle structure and the crystallizer structure.

[0016] Preferably, the steel material properties and process parameters include: steel liquid density, steel liquid specific heat capacity, steel liquid thermal conductivity, steel liquid phase, steel liquid solid phase, steel solidification latent heat, steel liquid casting superheat, steel liquid initial temperature, casting speed;

[0017] The boundary conditions for setting the flow and heat transfer model include: velocity inlet flow velocity, velocity inlet turbulent kinetic energy, velocity inlet turbulent kinetic energy dissipation rate, and billet surface heat flux density.

[0018] Preferably, in step 1, the specific steps of calculating the temperature field in the crystallizer and the distribution of the solidified shell under the flow of molten steel are: using a finite volume method solver to simulate and calculate the molten steel flow field, temperature field and solidified shell distribution field of the profiled billet in the crystallizer considering the immersed nozzle structure, and according to the calculation results, analyzing the flow characteristics of the molten steel in the crystallizer of the large-section profiled billet, the surface temperature distribution characteristics of the casting billet and the solidified shell distribution characteristics, and obtaining the influence of the molten steel flow process on the heat transfer process.

[0019] Preferably, in step 2, the specific steps of determining the cooling intensity required for each circumferential region and completing the preliminary design of the copper plate cooling water seam structure are: (1) based on the steel liquid flow field in the large-section profiled billet crystallizer, the temperature distribution of the billet surface in the cross-section circumferential direction, and the distribution of the solidified billet shell, obtain the temperature difference of each area on the billet surface in the circumferential direction and the thickness difference of the solidified billet shell, and determine the cooling intensity required for each circumferential region; (2) according to the cross-sectional structure of the profiled billet and the difference in cooling intensity required for each circumferential region, differentiate the copper plate cooling water seams in different regions to complete the preliminary design of the copper plate cooling water seam structure. Among them, the copper plate cooling structure includes the shape, size, cooling water volume, and distance of the water seam from the hot surface of the copper plate.

[0020] Preferably, in step 3, the three-dimensional flow and heat transfer coupling model of the large-section profiled blank crystallizer copper plate-molten steel-cooling water includes: a geometric model and its corresponding flow and heat transfer calculation model; the three-dimensional flow and heat transfer coupling model of the large-section profiled blank crystallizer copper plate-molten steel-cooling water includes: a turbulent flow model of the molten steel in the crystallizer, a laminar flow model of the cooling water in the cooling water gap, a heat conduction and convection heat transfer model between the molten steel and the copper plate, and a convection heat transfer model at the interface between the copper plate and the cooling water gap;

[0021] Preferably, in step 3, the specific steps of establishing the three-dimensional flow and heat transfer coupling model of the copper plate-molten steel-cooling water of the large-section profiled blank crystallizer are: (1) meshing the geometric model and setting the material properties of the steel grade and the process parameters; (2) setting boundary conditions for the flow and heat transfer model according to the submerged nozzle structure and the crystallizer structure, and the specific steps are: using a finite volume method solver to simulate and calculate the profiled blank molten steel flow field, molten steel temperature field, crystallizer copper plate temperature field, and solidified blank shell distribution field in the crystallizer under the consideration of the submerged nozzle structure and the crystallizer cooling water seam structure;

[0022] The geometric model includes a crystallizer composed of copper plates with cooling water gaps, cooling water in the water gaps of the crystallizer copper plates, and molten steel in the crystallizer;

[0023] The boundary conditions include: the inlet flow velocity of the immersed nozzle velocity, the turbulent kinetic energy of the immersed nozzle velocity, the turbulent kinetic energy dissipation rate of the immersed nozzle velocity, the inlet temperature of the immersed nozzle velocity, the thermal resistance between the copper plate and the molten steel, the convection heat transfer coefficient between the copper plate and the cooling water, the inlet flow velocity of the cooling water gap velocity, and the inlet temperature of the cooling water gap velocity.

[0024] Preferably, in step 4, the specific steps of determining the adjustment strategy of the cooling intensity of each area on the surface of the ingot according to the difference between the simulation results and the production demand standard, and optimizing the cooling water gap of the copper plate are:

[0025] Based on the calculation results of the copper plate-molten steel-cooling water flow and heat transfer coupling model, the distribution of ingot temperature and shell thickness is obtained by comprehensively considering the influence of the immersed nozzle and copper plate cooling structure. According to the difference between the simulation results of temperature and shell thickness and the required standards, the distribution uniformity of the ingot surface temperature, shell thickness and copper plate hot surface temperature in the billet drawing direction and circumferential direction is analyzed, and compared with the actual industrial production uniformity requirement standard, the adjustment strategy of the cooling intensity of each area on the ingot surface is determined.

[0026] The present invention has the following advantages:

[0027] (1) The optimal crystallizer cooling water gap designed by the present invention can effectively improve the heat transfer uniformity between the large-section special-shaped billet crystallizer copper plate and the molten steel, reduce the risk of billet crack defects, improve the billet product quality and extend the service life of the crystallizer copper plate.

[0028] (2) The three-dimensional flow and heat transfer coupling model of copper plate-molten steel-cooling water in the large-section special-shaped billet crystallizer described in the present invention fully considers the interaction between the copper plate, molten steel and cooling water, and accurately sets the boundary conditions required for optimizing the design of the crystallizer cooling water seam structure. The simulation results are more in line with the actual production process, and the optimal crystallizer cooling water seam structure finally obtained is more in line with the actual industrial production needs.

[0029] (3) The design method of the cooling water seam structure of the large-section special-shaped billet crystallizer described in the present invention can effectively consider the influence of the molten steel flow on the solidification process of the ingot, thereby obtaining more accurate temperature distribution characteristics of the copper plate and the ingot, and finally more accurately obtaining the design of the cooling water seam of the copper plate of the large-section special-shaped billet crystallizer under a specific immersion nozzle structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A flow chart of the steps of the design method of the cooling water seam structure of the large-section profiled blank crystallizer of the present invention;

[0031] Figure 2 It is a schematic diagram of a geometric model of a steel liquid calculation domain of a large-section profiled billet crystallizer created by three-dimensional software in an embodiment of the present invention;

[0032] Figure 3 It is a schematic diagram of the initial cooling water seam structure design of a large-section profiled blank crystallizer created by three-dimensional software in an embodiment of the present invention;

[0033] Figure 4 It is a partial schematic diagram of the geometric model of the initial cooling water seam structure of the large-section profiled blank crystallizer created by three-dimensional software in an embodiment of the present invention;

[0034] Figure 5 The figures are comparison diagrams of the circumferential thickness distribution of the billet shell at the outlet of the large-section profiled billet crystallizer under three different conditions; among them, (a) is the circumferential thickness distribution diagram of the billet shell at the outlet of the large-section profiled billet crystallizer without considering the flow of molten steel; (b) is the circumferential thickness distribution diagram of the billet shell at the outlet of the large-section profiled billet crystallizer under the initial water gap structure design scheme after considering the flow of molten steel; (b) is the circumferential thickness distribution diagram of the billet shell at the outlet of the large-section profiled billet crystallizer under the final water gap structure design scheme after considering the flow of molten steel;

[0035] Figure 6 This is a diagram showing the distribution of shell thickness at various circumferential characteristic points at the exit of the large-section profiled blank crystallizer;

[0036] Figure 7 A schematic diagram for selecting the circumferential characteristic point positions of large-section profile blanks;

[0037] Figure 8 It is a schematic diagram of the final cooling water seam structure design obtained after optimization of the large-section profiled blank crystallizer created by three-dimensional software in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The present invention is described in detail below in conjunction with specific embodiments. It should be noted that the following embodiments are only further descriptions of the present invention, but the protection scope of the present invention is not limited to the following embodiments.

[0039] Example 1

[0040] This embodiment relates to a design method for a cooling water seam structure of a profiled blank crystallizer. Figure 1 As shown, the following steps are included:

[0041] Step 1: Based on the structure of the crystallizer submerged nozzle and the cross-sectional shape of the crystallizer, a three-dimensional flow and heat transfer coupling model of molten steel in the large-section profiled billet crystallizer without considering the copper plate of the crystallizer is established. The three-dimensional flow and heat transfer coupling model of molten steel in the large-section profiled billet crystallizer includes a geometric model and a flow and heat transfer calculation model corresponding to the geometric model. The geometric model is meshed, and the material properties and process parameters of the steel grade are set; according to the structure of the submerged nozzle and the crystallizer structure, the boundary conditions of the flow and heat transfer model are set.

[0042] Step 2: Use the finite volume method solver to simulate and calculate the flow field, temperature field and solidified shell distribution field of the molten steel in the crystallizer under the submerged nozzle structure. Analyze the flow characteristics of the molten steel in the crystallizer of the large-section shaped billet, the surface temperature distribution characteristics of the billet and the distribution characteristics of the solidified shell, and obtain the influence of the molten steel flow process on the heat transfer process.

[0043] Step 3: Based on the steel liquid flow field in the large-section profiled billet crystallizer, the temperature distribution of the billet surface in the cross-section circumferential direction, and the distribution of the solidified billet shell, the temperature difference of each area on the billet surface in the circumferential direction and the thickness difference of the solidified billet shell are obtained, and the cooling intensity required in each circumferential area is determined. According to the cross-sectional structure of the profiled billet and the difference in cooling intensity required in each circumferential area, the copper plate cooling water seams in different areas are arranged differently to complete the preliminary design of the copper plate cooling water seam structure.

[0044] Step 4: According to the copper plate cooling water seam structure, a three-dimensional flow and heat transfer coupling model of copper plate-molten steel-cooling water in the large-section profiled blank crystallizer is established. The three-dimensional flow and heat transfer coupling model of copper plate-molten steel-cooling water in the large-section profiled blank crystallizer includes a geometric model and a flow and heat transfer calculation model corresponding to the geometric model. The geometric model is meshed, and the steel material properties and process parameters are set; according to the immersion nozzle structure and the crystallizer structure, the boundary conditions of the flow and heat transfer model are set.

[0045] Step 5: Use the finite volume method solver to simulate and calculate the flow field of the molten steel in the mold, the temperature field of the molten steel, the temperature field of the copper plate in the mold, and the distribution field of the solidified shell, considering the structure of the immersed nozzle and the cooling water seam of the mold. Analyze the uniformity of the surface temperature of the billet, the thickness of the billet shell, and the hot surface temperature of the copper plate in the direction of the billet drawing and the circumferential direction, and compare them with the actual industrial production uniformity requirements. According to the difference between the simulation results of temperature and billet shell thickness and the production requirements, determine the adjustment strategy of the cooling intensity of each area on the surface of the billet.

[0046] Step 6: According to the adjustment strategy of cooling intensity in each area, optimize the copper plate cooling structure, and repeat steps 4 and 5. Finally, the optimal copper plate cooling water seam structure is obtained under the action of molten steel with a specific immersion nozzle structure, and the temperature and shell thickness distribution of the casting billet meet the production requirements.

[0047] The specific method is as follows:

[0048] Step 1: Establish a three-dimensional flow and heat transfer coupling model of molten steel in a large-section profiled billet crystallizer. The three-dimensional flow and heat transfer coupling model of molten steel in a large-section profiled billet crystallizer includes a geometric model and a flow and heat transfer calculation model corresponding to the geometric model. The geometric model is meshed, and the steel material properties and process parameters are set; boundary conditions are set for the flow and heat transfer model according to the submerged nozzle structure and the crystallizer structure.

[0049] According to the structure of the submerged nozzle, the nozzle insertion position, and the cross-sectional dimensions of the crystallizer, a geometric model of the calculation domain of the molten steel is established. The geometric model of the calculation domain is as follows: Figure 2 shown.

[0050] Thermophysical property parameters include density of molten steel, specific heat capacity of molten steel, thermal conductivity of molten steel, liquidus line of steel grade, solidus line of steel grade, latent heat of solidification of steel grade, superheat of molten steel casting, and casting speed; the flow and heat transfer coupling model includes the k-ε turbulence model, energy model, solidification and melting model of molten steel in the crystallizer; boundary conditions include: velocity inlet flow velocity of submerged nozzle, turbulent kinetic energy of submerged nozzle velocity inlet, turbulent kinetic energy dissipation rate of velocity inlet, and heat flux density on the surface of ingot.

[0051] Step 2: Use the finite volume method solver to simulate and calculate the flow field, temperature field and solidified shell distribution field of the molten steel in the crystallizer under the submerged nozzle structure. Analyze the flow characteristics of the molten steel in the crystallizer of the large-section shaped billet, the surface temperature distribution characteristics of the billet and the distribution characteristics of the solidified shell, and obtain the influence of the molten steel flow process on the heat transfer process.

[0052] According to the calculation results of flow field, temperature field and solidified shell distribution field, the molten steel flow velocity, billet surface temperature and solidified shell thickness data at each circumferential characteristic point at different height cross sections along the billet drawing direction are extracted to obtain the corresponding relationship between the billet surface temperature and the solidified shell thickness distribution under different molten steel flow velocities.

[0053] Step 3: Based on the steel liquid flow field in the large-section profiled billet crystallizer, the temperature distribution of the billet surface in the cross-section circumferential direction, and the distribution of the solidified billet shell, the temperature difference of each area on the billet surface in the circumferential direction and the thickness difference of the solidified billet shell are obtained, and the cooling intensity required in each circumferential area is determined. According to the cross-sectional structure of the profiled billet and the difference in cooling intensity required in each circumferential area, the copper plate cooling water seams in different areas are arranged differently to complete the preliminary design of the copper plate cooling water seam structure.

[0054] The copper plate cooling structure includes the shape, size, number, cooling water volume, and distance between the water seam and the hot surface of the copper plate. The preliminary design of the copper plate cooling water seam structure is shown in Figure 3 shown.

[0055] Step 4: According to the copper plate cooling water seam structure, a three-dimensional flow and heat transfer coupling model of copper plate-molten steel-cooling water in the large-section profiled blank crystallizer is established. The three-dimensional flow and heat transfer coupling model of copper plate-molten steel-cooling water in the large-section profiled blank crystallizer includes a geometric model and a flow and heat transfer calculation model corresponding to the geometric model. The geometric model is meshed, and the steel material properties and process parameters are set; according to the immersion nozzle structure and the crystallizer structure, the boundary conditions of the flow and heat transfer model are set.

[0056] The geometric model includes a crystallizer composed of copper plates with cooling water gaps, cooling water in the water gaps of the crystallizer copper plates, and molten steel in the crystallizer. The partial schematic diagram of the geometric model is shown in Figure 4 As shown;

[0057] The three-dimensional flow and heat transfer coupling model of copper plate-molten steel-cooling water in large-section profiled billet crystallizer includes the turbulence model of molten steel in the crystallizer, the laminar flow model of cooling water in the cooling water gap, the heat conduction and convection heat transfer model between molten steel and copper plate, and the convection heat transfer model at the interface between copper plate and cooling water gap.

[0058] The boundary conditions include: the inlet flow velocity of the immersed nozzle velocity, the turbulent kinetic energy of the immersed nozzle velocity, the turbulent kinetic energy dissipation rate of the immersed nozzle velocity, the inlet temperature of the immersed nozzle velocity, the thermal resistance between the copper plate and the molten steel, the convection heat transfer coefficient between the copper plate and the cooling water, the inlet flow velocity of the cooling water gap velocity, and the inlet temperature of the cooling water gap velocity.

[0059] Step 5: Use the finite volume method solver to simulate and calculate the flow field of the molten steel in the mold, the temperature field of the molten steel, the temperature field of the copper plate in the mold, and the distribution field of the solidified shell. The results of the shell thickness distribution at the mold outlet without considering the immersion nozzle and considering the immersion nozzle are as follows: Figure 5 , Figure 6 shown.

[0060] The distribution uniformity of the billet surface temperature, billet shell thickness and copper plate hot surface temperature in the billet drawing direction and circumferential direction was analyzed, and compared with the actual industrial production uniformity requirement standards. According to the difference between the simulation results of temperature and billet shell thickness and the required standards, the adjustment strategy of the cooling intensity of each area on the billet surface was determined.

[0061] Among them, the actual production needs include the peak temperature of the hot surface of the copper plate, the maximum difference in the hot surface temperature of the copper plate, the peak temperature of the surface of the ingot at the crystallizer outlet, the valley value of the surface temperature of the ingot at the crystallizer outlet, the maximum circumferential difference in the surface temperature of the ingot at the crystallizer outlet, the peak value of the thickness of the solidified ingot shell at the crystallizer outlet, the valley value of the thickness of the solidified ingot shell at the crystallizer outlet, and the maximum circumferential difference in the thickness of the solidified ingot shell at the crystallizer outlet.

[0062] Step 6: Based on the comparison between the calculation results of the copper plate-molten steel flow and heat transfer coupling model and the actual production needs, the shape, size, quantity, cooling water volume, and hot surface distance of the copper plate cooling water slits are redesigned, and the corresponding large-section profiled billet crystallizer copper plate-molten steel-cooling water three-dimensional flow and heat transfer coupling model is established. Combined with the model and related boundary conditions, the profiled billet crystallizer copper plate-molten steel three-dimensional flow and heat transfer coupling model calculation is re-performed. By comparing the billet temperature and the solidified billet shell distribution, see Figure 7As shown in the figure, the copper plate cooling water gap structure of the crystallizer is repeatedly optimized until the production process requirements are met, and finally the optimal copper plate cooling water gap structure design of the target large-section special-shaped blank crystallizer is obtained. The copper plate cooling water gap structure finally optimized and determined is as follows Figure 8 shown.

[0063] The present invention uses three-dimensional flow and heat transfer coupling calculation to obtain the heat transfer characteristics of the copper plate and the ingot under the influence of the molten steel flow, and finally optimizes the design of the crystallizer copper plate cooling water gap suitable for actual industrial production according to the copper plate and ingot temperature distribution and solidified ingot shell distribution under different copper plate cooling water gap structures. The method of the present invention can effectively improve the heat transfer uniformity between the copper plate and the molten steel, reduce the risk of ingot crack defects, improve the ingot product quality and extend the service life of the crystallizer copper plate.

[0064] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which will not affect the essence of the present invention.

Claims

1. A method for designing cooling water seam structure of large-section profiled blank crystallized copper plate, characterized in that: The following steps are involved: Step 1, establishing a three-dimensional flow and heat transfer coupling model of molten steel in a profiled blank crystallizer, and calculating the temperature field in the crystallizer and the distribution of the solidified blank shell under the consideration of the flow of molten steel; Step 2, determine the cooling intensity required for each circumferential area and complete the preliminary design of the copper plate cooling water seam structure; Step 3: Establish a three-dimensional flow and heat transfer coupling model of copper plate-molten steel-cooling water in a large-section profiled blank crystallizer based on the cooling structure design, and calculate the flow and heat transfer characteristics of the molten steel in the crystallizer considering the cooling water seam structure of the crystallizer; Step 4: According to the difference between the simulation results and the production demand standards, the adjustment strategy of the cooling intensity of each area on the surface of the ingot is determined, and the cooling water gap of the copper plate is optimized; Step 5, repeating the copper plate-molten steel-cooling water flow heat transfer coupling model calculation and cooling water seam structure optimization; Step 6, finally obtaining the optimal copper plate cooling water seam structure in which the temperature of the ingot and the thickness distribution of the ingot shell under the action of the molten steel of the specific immersion nozzle structure meet the production requirements.

2. The method for designing cooling water seam structure of large-section profiled blank crystallized copper plate according to claim 1, characterized in that: In step 1, the three-dimensional flow and heat transfer coupling model of molten steel in the profiled billet crystallizer includes: a geometric model and a corresponding flow and heat transfer calculation model.

3. The method for designing cooling water seam structure of large-section profiled blank crystallized copper plate according to claim 2, characterized in that: The three-dimensional flow and heat transfer coupling model of molten steel in the profiled billet crystallizer comprises: a turbulence model of the molten steel in the crystallizer, a molten steel heat transfer model, and a molten steel solidification model.

4. The method for designing cooling water seam structure of large-section profiled blank crystallized copper plate according to claim 1, characterized in that: In step 1, the specific steps of establishing the three-dimensional flow and heat transfer coupling model of molten steel in the special-shaped billet crystallizer are: (1) meshing the geometric model and setting the material properties and process parameters of the steel grade; (2) setting boundary conditions for the flow and heat transfer model according to the submerged nozzle structure and the crystallizer structure.

5. The method for designing cooling water seam structure of large-section profiled blank crystallized copper plate according to claim 4, characterized in that: The steel material properties and process parameters include: steel liquid density, steel liquid specific heat capacity, steel liquid thermal conductivity, steel liquid phase, steel liquid solid phase, steel solidification latent heat, steel liquid casting superheat, steel liquid initial temperature, casting speed; The boundary conditions for setting the flow and heat transfer model include: velocity inlet flow velocity, velocity inlet turbulent kinetic energy, velocity inlet turbulent kinetic energy dissipation rate, and billet surface heat flux density.

6. The method for designing cooling water seam structure of large-section profiled blank crystallized copper plate according to claim 1, characterized in that: In step 1, the specific steps of calculating the temperature field in the crystallizer and the distribution of the solidified shell under the consideration of the flow of molten steel are as follows: a finite volume method solver is used to simulate and calculate the flow field, temperature field and solidified shell distribution field of the molten steel of the profiled billet in the crystallizer considering the immersed nozzle structure; according to the calculation results, the flow characteristics of the molten steel in the crystallizer of the large-section profiled billet, the surface temperature distribution characteristics of the ingot and the solidified shell distribution characteristics are analyzed to obtain the influence of the molten steel flow process on the heat transfer process.

7. The method for designing cooling water seam structure of large-section profiled blank crystallized copper plate according to claim 1, characterized in that: In step 2, the specific steps of determining the cooling intensity required for each circumferential region and completing the preliminary design of the copper plate cooling water seam structure are as follows: (1) based on the steel liquid flow field in the large-section special-shaped billet crystallizer, the temperature distribution of the billet surface in the cross-section circumferential direction, and the distribution of the solidified billet shell, the temperature difference of each area on the billet surface in the circumferential direction and the thickness difference of the solidified billet shell are obtained to determine the cooling intensity required for each circumferential region; (2) According to the cross-sectional structure of the special-shaped billet and the difference in cooling intensity required in each circumferential area, the copper plate cooling water seams in different areas are arranged differently to complete the preliminary design of the copper plate cooling water seam structure.

8. The method for designing cooling water seam structure of large-section profiled blank crystallized copper plate according to claim 1, characterized in that: In step 3, the three-dimensional flow and heat transfer coupling model of the large-section profiled blank crystallizer copper plate-molten steel-cooling water includes: a geometric model and a corresponding flow and heat transfer calculation model.

9. The method for designing cooling water seam structure of large-section profiled blank crystallized copper plate according to claim 1, characterized in that: In step 3, the specific steps of establishing the three-dimensional flow and heat transfer coupling model of the copper plate-molten steel-cooling water of the large-section profiled blank crystallizer are: (1) meshing the geometric model and setting the material properties of the steel grade and the process parameters; (2) setting boundary conditions for the flow and heat transfer model according to the submerged nozzle structure and the crystallizer structure; the specific steps are: using a finite volume method solver to simulate and calculate the profiled blank steel liquid flow field, steel liquid temperature field, crystallizer copper plate temperature field, and solidified blank shell distribution field in the crystallizer under the consideration of the submerged nozzle structure and the crystallizer cooling water seam structure; The geometric model includes a crystallizer composed of copper plates with cooling water gaps, cooling water in the water gaps of the crystallizer copper plates, and molten steel in the crystallizer; The boundary conditions include: the inlet flow velocity of the immersed nozzle velocity, the turbulent kinetic energy of the immersed nozzle velocity, the turbulent kinetic energy dissipation rate of the immersed nozzle velocity, the inlet temperature of the immersed nozzle velocity, the thermal resistance between the copper plate and the molten steel, the convection heat transfer coefficient between the copper plate and the cooling water, the inlet flow velocity of the cooling water gap velocity, and the inlet temperature of the cooling water gap velocity.

10. The method for designing cooling water seam structure of large-section profiled blank crystallized copper plate according to claim 1, characterized in that: In step 4, the specific steps of determining the adjustment strategy of the cooling intensity of each area on the surface of the ingot according to the difference between the simulation results and the production demand standard and optimizing the cooling water gap of the copper plate are as follows: Based on the calculation results of the copper plate-molten steel-cooling water flow and heat transfer coupling model, the distribution of ingot temperature and shell thickness is obtained by comprehensively considering the influence of the immersed nozzle and copper plate cooling structure. According to the difference between the simulation results of temperature and shell thickness and the required standards, the adjustment strategy of the cooling intensity of each area on the surface of the ingot is determined.

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