Finite element method for calculating temperature distribution of steel strip in continuous hot galvanizing process

Abstract

The invention relates to a finite element method for calculating temperature distribution of a steel strip in a continuous hot galvanizing process, and belongs to the technical field of hot galvanizing methods. According to the technical scheme, the method comprises the steps that relevant sizes and technological parameters of a continuous hot galvanizing production line are obtained; model establishment and grid division are conducted, a three-dimensional model is established according to the related size, the model comprises molten zinc and a steel belt, and the molten zinc and the steel belt are set to be solid models; and setting boundary conditions, performing heat exchange calculation, and processing a calculation result. The method has the beneficial effects that the method is used for analyzing the temperature distribution of the steel strip in the hot galvanizing process and analyzing the flow field and the temperature field of molten zinc; and the change of working condition parameters such as the temperature of the steel brought into the zinc pot, the moving speed of the steel strip, the thickness and width of the steel strip, the temperature and depth of molten zinc and the like is accurately responded, so that the optimization of the continuous hot galvanizing process is guided.

Description

TECHNICAL FIELD

[0001] The application relates to a finite element method for calculating the temperature distribution of a steel strip in a continuous hot galvanizing process and belongs to the technical field of hot galvanizing methods. BACKGROUND

[0002] The hot galvanizing quality of a steel strip seriously affects the corrosion resistance of galvanized steel, and the hot galvanizing process of the steel strip is mainly carried out in a zinc pot, and the steel strip is continuously immersed in molten zinc liquid to realize hot dip galvanizing. Therefore, the hot galvanizing process occurs in a 'black box', and it is difficult to effectively monitor the same. At present, many scholars use physical model method, finite element method and other analysis means to study the continuous hot galvanizing process of the steel strip. Wang Lu uses a water model test to study the zinc pot flow field distribution form, bottom slag distribution law and scum entrainment state under different steel strip specifications, steel strip speed and other production parameters. Liu Fang also uses a water model and combines a three-dimensional laser Doppler velocimetry system to investigate the influence of the steel strip speed and the inductor power on the zinc pot flow field. FIlinca and DJ Willis use a finite element method to analyze the molten zinc liquid flow field and temperature field in the continuous hot galvanizing process. Park uses a finite element method to calculate the changes of the molten zinc liquid flow field and temperature field caused by an electromagnetic heating device. Although the above researches systematically study the molten zinc liquid flow field and temperature field distribution in the continuous hot galvanizing process, the physical model and the finite element calculation model developed by the researches do not analyze the heat exchange process between the steel strip and the molten zinc liquid. Therefore, in order to focus on analyzing the temperature distribution of the steel strip in the continuous hot galvanizing process and taking into account the analysis of the molten zinc liquid flow field and temperature field, the application provides a finite element method for calculating the temperature distribution of a steel strip in a continuous hot galvanizing process. SUMMARY

[0003] The application aims to provide a finite element method for calculating the temperature distribution of a steel strip in a continuous hot galvanizing process. By establishing a model and grid division, setting boundary conditions, carrying out heat exchange calculation and processing the calculation results, the method not only can be used for analyzing the temperature distribution of the steel strip in the hot galvanizing process, but also can take into account the analysis of the molten zinc liquid flow field and temperature field. The method can accurately respond to the changes of the steel strip temperature entering the zinc pot, the steel strip moving speed, the steel strip thickness, the steel strip width, the molten zinc liquid temperature, the molten zinc liquid depth and other working condition parameters, and can guide the optimization of the continuous hot galvanizing process, thereby effectively solving the above problems existing in the background art.

[0004] The technical scheme of the application is as follows: a finite element method for calculating the temperature distribution of a steel strip in a continuous hot galvanizing process, comprising the following steps: Step S1: obtaining relevant dimensions and process parameters of a continuous hot galvanizing production line; Step S2: establishing a model and grid division, establishing a three-dimensional model according to the relevant dimensions, and the model comprising a molten zinc liquid and a steel strip, and the two are respectively set as solid models; Step S3, setting boundary conditions, carrying out heat exchange calculation and processing the calculation results, setting the speed inlet boundary condition through the position where the steel strip enters the zinc pot, and setting the temperature as the temperature of the steel strip entering the zinc pot, realizing the movement of the steel strip and heat exchange calculation.

[0005] In the step S1, the size parameters include the size and spatial position of the furnace nose, the sinking roll, the guide roll, the width and thickness of the steel strip, and the length, width and depth parameters of the molten zinc liquid; the process parameters include the temperature of the steel strip entering the zinc pot, the temperature of the molten zinc liquid, the moving speed of the steel strip and the rotating speed of the sinking roll and the guide roll.

[0006] In the step S2, when establishing the model, the outer wall surface of the zinc pot can be omitted, and the sinking roll and the guide roll can be established only as a wall surface without being set as a solid model.

[0007] In the step S2, in the mesh division process, it is required to ensure that the steel strip solid model has at least one layer of mesh in the thickness direction.

[0008] In the step S3, the interface between the steel strip and the molten zinc liquid is set as a thermal coupling wall surface (Coupled Wall), and the wall surface is set as a wall boundary condition of no slip (No Slip) and moving wall (Moving Wall).

[0009] In the step S3, the calculation process is solved by the Fluent solver, the calculation process selects a pressure-based solver (Pressure-Based Solver), the calculation process is a steady process (Steady), and after the calculation is completed, the calculation result is processed by CFD-POST.

[0010] The beneficial effects of the present application are: through the establishment of the model and the mesh division, the setting of the boundary conditions, the heat exchange calculation and the processing of the calculation results, not only the temperature distribution of the steel strip in the hot galvanizing process can be analyzed, but also the flow field and the temperature field of the molten zinc liquid can be analyzed; the working condition parameter changes such as the temperature of the steel strip entering the zinc pot, the moving speed of the steel strip, the thickness and width of the steel strip, the temperature of the molten zinc liquid and the depth can be accurately responded, thereby guiding the optimization of the continuous hot galvanizing process. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is the mesh model of the steel strip temperature distribution calculation in the continuous hot galvanizing process of the present application; Figure 2 is the temperature distribution diagram of the steel strip in the hot galvanizing process when the temperature of the steel strip entering the zinc pot is 430 DEG C in the present application; Figure 3 is the temperature distribution diagram of the steel strip in the hot galvanizing process when the temperature of the steel strip entering the zinc pot is 465 DEG C in the present application; Figure 4This is a flow field diagram of molten zinc liquid during the hot-dip galvanizing process of the steel strip of the present invention; Figure 5 This is a temperature distribution diagram of the steel strip of the present invention during the hot-dip galvanizing process when the strip width is 1000mm. Figure 6 This is a temperature distribution diagram of the steel strip of the present invention during the hot-dip galvanizing process when the strip width is 1300mm. Figure 7 This is a temperature distribution diagram of the steel strip of the present invention during the hot-dip galvanizing process when the steel strip thickness is 0.5 mm. Figure 8 This is a temperature distribution diagram of the steel strip of the present invention during the hot-dip galvanizing process when the steel strip thickness is 2.0 mm. Figure 9 This is a temperature distribution diagram of the steel strip during the hot-dip galvanizing process when the steel strip drawing speed is 1.4 m / s. Figure 10 This is a temperature distribution diagram of the steel strip during the hot-dip galvanizing process when the steel strip drawing speed is 2.2 m / s. Detailed Implementation

[0012] To make the purpose, technical solutions, and advantages of the invention's embodiments clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only a small part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0013] A finite element method for calculating the temperature distribution of steel strip during continuous hot-dip galvanizing includes the following steps: Step S1: Obtain the relevant dimensions and process parameters of the continuous hot-dip galvanizing production line; Step S2: Establish the model and mesh. Based on the relevant dimensions, establish a three-dimensional model, which includes molten zinc liquid and steel strip, and set them as solid models respectively. Step S3: Set boundary conditions, perform heat transfer calculations and process the calculation results. Set the velocity inlet boundary condition by the position of the steel strip entering the zinc pot, and set the temperature to the temperature at which the steel strip enters the zinc pot, so as to realize the movement of the steel strip and the heat transfer calculation.

[0014] In step S1, the dimensional parameters include the dimensions and spatial positions of the furnace nose, submerged roller, and guide roller, the width and thickness of the steel strip, and the length, width, and depth parameters of the molten zinc liquid; the process parameters include the temperature of the steel strip entering the zinc pot, the temperature of the molten zinc liquid, the moving speed of the steel strip, and the rotational speed of the submerged roller and guide roller.

[0015] In step S2, the creation of the outer wall of the zinc pot can be omitted when building the model, and the submerged roller and guide roller can also be created only as wall surfaces without being set as solid models.

[0016] In step S2, during the mesh generation process, it is necessary to ensure that the steel strip solid model has at least one layer of mesh in the thickness direction.

[0017] In step S3, the interface between the steel strip and the molten zinc is set as a thermally coupled wall, and the wall is set as a non-slip and movable wall boundary condition.

[0018] In step S3, the calculation process is performed by the Fluent solver. The calculation process is based on a pressure solver and is a steady-state process. After the calculation is completed, the calculation results are processed using CFD-POST. Example 1

[0019] The present invention calculates the temperature distribution of steel strip during hot-dip galvanizing at different zinc bath temperatures, comprising the following steps: Step 1. Obtain the relevant dimensions and process parameters of the continuous hot-dip galvanizing production line. Dimensional parameters include the size and spatial position of the furnace nose, submerged roller, and guide roller; the width and thickness of the steel strip; and the length, width, and depth of the molten zinc. Process parameters include the steel strip's entry temperature into the zinc bath, the temperature of the molten zinc, the steel strip's moving speed, and the rotational speeds of the submerged roller and guide roller.

[0020] Step 2. Model Building and Mesh Generation. A 3D model is built based on the relevant dimensions. The model includes molten zinc and a steel strip, both of which are set as solid models. The creation of the outer wall of the zinc pot can be omitted; the submerged roller and guide roller can also be created only as wall models without being set as solid models. During mesh generation, it is necessary to ensure that the steel strip solid model has at least one layer of mesh in the thickness direction. To reduce computational load while ensuring the accuracy of the calculation results, a half-symmetric model in the width direction of the zinc pot is used for calculation, and the symmetry plane uses symmetry wall boundary conditions (Symmetry), such as... Figure 1 As shown.

[0021] Step 3. Set boundary conditions, perform heat transfer calculations, and process the results. The interface between the steel strip and the molten zinc needs to be set as a thermally coupled wall, and this wall should be set as a no-slip and movable wall boundary condition. Set velocity inlet boundary conditions at the point where the steel strip enters the zinc pot, with the temperature set to the steel strip inlet temperature (430℃, 465℃, and 490℃). Set velocity outlet boundary conditions at the point where the steel strip exits the zinc pot. After setting the boundary conditions, use the Fluent solver for solving. The calculation process uses a pressure-based solver and is a steady-state process. After the calculation is completed, use CFD-POST to process the results. Example 2

[0022] Using this invention, the temperature distribution of the steel strip during continuous hot-dip galvanizing was calculated when the steel strip drawing speed was 1.8 m / s, the thickness was 1.5 mm, the temperature in the zinc pot was 470℃, and the steel strip width was 1000 mm, 1100 mm, 1200 mm, and 1300 mm. Example 3

[0023] Using this invention, the temperature distribution of the steel strip during continuous hot-dip galvanizing was calculated when the steel strip drawing speed was 1.8 m / s, the temperature in the zinc pot was 470℃, the steel strip width was 1200 mm, and the thickness was 0.5 mm, 1 mm, 1.5 mm, and 2 mm. Example 4

[0024] Using this invention, the temperature distribution of the steel strip during continuous hot-dip galvanizing was calculated when the steel strip temperature at the zinc pot was 470℃, the steel strip width was 1200mm, the thickness was 1mm, and the drawing speed was 1.4m / s, 1.8m / s, and 2.2m / s.

[0025] Matters not covered in this invention are common knowledge.

[0026] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A finite element method for calculating the temperature distribution of steel strip during continuous hot-dip galvanizing, characterized in that... Includes the following steps: Step S1: Obtain the relevant dimensions and process parameters of the continuous hot-dip galvanizing production line; Step S2: Establish the model and mesh. Based on the relevant dimensions, establish a three-dimensional model, which includes molten zinc liquid and steel strip, and set them as solid models respectively. Step S3: Set boundary conditions, perform heat transfer calculations and process the calculation results. Set the velocity inlet boundary condition by the position of the steel strip entering the zinc pot, and set the temperature to the temperature at which the steel strip enters the zinc pot, so as to realize the movement of the steel strip and the heat transfer calculation.

2. The finite element method for calculating the temperature distribution of steel strip during continuous hot-dip galvanizing according to claim 1, characterized in that: In step S1, the dimensional parameters include the dimensions and spatial positions of the furnace nose, submerged roller, and guide roller, the width and thickness of the steel strip, and the length, width, and depth parameters of the molten zinc liquid; the process parameters include the temperature of the steel strip entering the zinc pot, the temperature of the molten zinc liquid, the moving speed of the steel strip, and the rotational speed of the submerged roller and guide roller.

3. The finite element method for calculating the temperature distribution of steel strip during continuous hot-dip galvanizing according to claim 1, characterized in that: In step S2, the creation of the outer wall of the zinc pot can be omitted when building the model, and the submerged roller and guide roller can also be created only as wall surfaces without being set as solid models.

4. The finite element method for calculating the temperature distribution of steel strip during continuous hot-dip galvanizing according to claim 1, characterized in that: In step S2, during the mesh generation process, it is necessary to ensure that the steel strip solid model has at least one layer of mesh in the thickness direction.

5. The finite element method for calculating the temperature distribution of steel strip during continuous hot-dip galvanizing according to claim 1, characterized in that: In step S3, the interface between the steel strip and the molten zinc is set as a thermally coupled wall, and the wall is set as a non-slip and movable wall boundary condition.

6. The finite element method for calculating the temperature distribution of steel strip during continuous hot-dip galvanizing according to claim 1, characterized in that: In step S3, the calculation process is performed by the Fluent solver. The calculation process is based on a pressure solver and is a steady-state process. After the calculation is completed, the calculation results are processed using CFD-POST.

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