A three-dimensional simulation method of heating performance of fiber bundle in high temperature carbonization furnace based on dynamic mesh method

Abstract

A three-dimensional simulation method for heating performance of a fiber bundle in a high-temperature carbonization furnace based on a dynamic mesh method relates to the technical field of a design simulation analysis method for a high-temperature carbonization furnace used in carbon fiber production. Aiming at the technical deficiencies of the three-dimensional simulation method in the design process of the existing high-temperature carbonization furnace, the method comprises: (1) establishing a three-dimensional simulation model; (2) transferring the model to the Global Mesh Setup module of the ICEM software for meshing; (3) transferring the model to the FLUENT module of the ANSYS software and setting boundary conditions; (4) obtaining the result through simulation operation, which is used as an indicator for determining the heating performance of the fiber bundle in the high-temperature carbonization furnace; (5) repeating steps (1)-(4), and realizing the visibility of the temperature field in the furnace cavity and the temperature field on the surface of the fiber bundle during the heating process through the temperature change cloud map of the detection surface, and outputting the result intuitively. It reduces costs, shortens product development cycles, and provides a basis for numerical simulation research.

Description

Technical Field

[0001] The invention relates to the technical field of design simulation analysis method of high-temperature carbonization furnace used in carbon fiber production. Background Art

[0002] Carbon fiber production is a high-energy-consuming industry, among which the high-temperature carbonization furnace is one of the largest energy consumers in carbon fiber production equipment. At the same time, the high-temperature carbonization furnace is also a key equipment for carbon fiber production, mainly used for high-temperature carbonization of pre-oxidized filaments to convert them into carbon fibers with a carbon content greater than 90%. The high-temperature carbonization furnace is an integration of high-temperature technology and high-temperature equipment, and the operating temperature is generally between 1000℃ and 1600℃. At present, in the production of carbon fibers, the quality of the products is mainly tested after the production process is completed, resulting in the inability to dynamically adjust the quality of the products during production, and it is difficult to improve the product qualification rate. The uniformity of the temperature field in the high-temperature carbonization furnace is crucial to the performance of the product, and the temperature in the furnace is above 1000℃, and conventional testing methods cannot meet the requirements. Therefore, it is necessary to select a reasonable design method to ensure that the furnace wall can reach a surface temperature that meets the specifications, so that the filament bundles are evenly heated in the furnace cavity, while reducing unit energy consumption. Summary of the invention

[0003] In summary, the present invention is aimed at the technical deficiency in the design process of existing high-temperature carbonization furnaces, that is, the lack of a three-dimensional simulation method for heating performance that can ensure that the furnace wall can reach a surface temperature that meets the specifications, so that the filament bundles are heated evenly in the furnace cavity, and at the same time reduce the unit energy consumption. A three-dimensional simulation method for heating performance of filament bundles in a high-temperature carbonization furnace based on a dynamic grid method is proposed.

[0004] In order to solve the technical problem proposed by the present invention, the technical solution adopted is:

[0005] A three-dimensional simulation method for heating performance of a tow in a high-temperature carbonization furnace based on a moving grid method, characterized in that the method comprises the following steps:

[0006] (1) Use the 3D CAD software SOLIDWORKS to establish a 3D simulation model of the fluid calculation domain of the high-temperature carbonization furnace muffle cavity and the heated filament bundle;

[0007] (2) The high-temperature carbonization furnace muffle cavity fluid calculation domain and the three-dimensional simulation model of the heated filament bundle established in step (1) are respectively transferred to the Global Mesh Setup module of the ICEM software. In the Global Mesh Setup module, the Volume Meshing Parameters are set to Tetra / Mixed for the meshing type. The high-temperature carbonization furnace muffle cavity fluid calculation domain and the three-dimensional simulation model of the heated filament bundle are meshed. The entire calculation domain adopts an unstructured grid, and the grid is encrypted near the wall surface of the filament bundle. According to the grid quality judgment standard in the ICEM software, the grid quality of the overall structure is ensured to be greater than 0.5. The names of the inlet and outlet and wall boundaries of all three-dimensional simulation models are defined, including the names of the filament bundle wall, the furnace cavity inlet and outlet, and the furnace cavity wall boundary.

[0008] (3) The meshed fluid calculation domain and the three-dimensional simulation model of the heated tow are transferred to the FLUENT module of the ANSYS software, and the boundary conditions are set;

[0009] (4) Set the temperature detection surface in the FLUENT module in the ANSYS software, and perform simulation calculations to obtain the results, which are used as indicators to determine the heating performance of the filament bundle in the high-temperature carbonization furnace; the process of setting the FLUENT module in the ANSYS software is as follows:

[0010] (4.1) Import the custom tow motion parameters compiled according to the process parameters in the User Defined option, control the motion state of the heated tow through UDF, and realize the motion process of the tow in the high-temperature carbonization furnace;

[0011] (4.2) In the General option, set the Gravitational Acceleration in the y direction to the preset value according to the actual situation, and set the time option to Transient transient heat transfer;

[0012] (4.3) Select Energy Equation in the Energy of Models option and select the laminar model in the Viscous Models option. In order to determine the state of airflow movement in the furnace cavity, the Reynolds number is introduced for description. The calculation formula of the Reynolds number is:

[0013]

[0014] Among them, v, ρ, μ are the velocity, density and viscosity coefficient of the fluid respectively, and d is the characteristic length; through the calculation of the Reynolds number, the turbulence model is selected as the laminar model;

[0015] (4.4) Select air and nitrogen in the Materials Fluid option section; establish the physical parameters of the tow in the Materials Solid option, including density, specific heat capacity, and thermal conductivity parameters;

[0016] (4.5) In the Cell Zone Conditions option, set Fluid1 to nitrogen and Fluid2 to oxygen; set Solid1 to tow;

[0017] (4.6) In the Boundary Conditions option, set the inlet boundary condition to Pressure-inlet, and set the Velocity Magnitude to the preset value according to actual requirements, set the Thermal option to udf tm-inlet, set the outlet boundary condition to Pressure-outlet, set one side of the wall to the convection heat transfer surface, UDF defines the comprehensive temperature value of the furnace wall air per hour, set the convection heat transfer coefficient to the preset value according to actual requirements, set other walls to adiabatic walls, and set the tow and gas contact surface to Coupled;

[0018] (4.7) In the Dynamic Mesh option, check the Activate Dynamic Mesh option, check the Smoothing and Remeshing options in the Mesh Methods option; define the motion zone in Dynamic Mesh Zones, select rigid wall under Zone Names, select Rigid Body in Type, and set the preview mesh motion in Preview Mesh Motion;

[0019] (4.8) After selecting Check Case, the calculation is performed. The calculation time is set according to the parameters in the actual project. The three-dimensional mathematical model of the full flow field calculation of the high-temperature carbonization furnace used for the calculation after selecting Check Case includes the continuity equation, momentum equation and energy equation, which are shown as follows:

[0020]

[0021] Where, ρ is fluid density; t is time; V is velocity vector, and u, v, w are the components of V in the x, y and z directions.

[0022] Navier-Stokes equation of momentum:

[0023]

[0024] Where μ is the dynamic viscosity, F bis the volume force on the infinitesimal element;

[0025] Energy conservation equation:

[0026]

[0027] Among them, C p —Specific heat capacity, T—temperature, k—fluid heat transfer coefficient, S T —viscous dissipation term;

[0028] (5) Under the same setting conditions, by setting different parameters for the high-temperature carbonization furnace muffle cavity fluid calculation domain and the three-dimensional simulation model of the heated filament bundle, and repeating steps (1)-(4) to perform multiple simulation calculations, the post-processing software CFD-POST is used to realize the visualization of the temperature field in the furnace cavity and the temperature field on the surface of the filament bundle during the heating process of the filament bundle from the temperature change cloud map of the detection surface, and the intuitive output result.

[0029] The technical solutions for further limiting the present invention include:

[0030] The parameters set for the three-dimensional simulation model of the high-temperature carbonization furnace muffle cavity fluid calculation domain and the heated filament bundle in step (1) include: the geometry and geometric dimensions of the muffle cavity, the geometry and geometric dimensions of the inlet and outlet seals, the inlet dimensions of the inlet and outlet sealed nitrogen pipes, the outlet dimensions of the nitrogen pipe, and the geometry and geometric dimensions of the heated filament bundle.

[0031] In step (4), the center point of the three-dimensional simulation model of the high-temperature carbonization furnace muffle cavity fluid calculation domain is selected as the detection surface, and the detection surface is the X-direction plane passing through the center point. The surface of the wire bundle is selected as the detection surface, and the detection surface is the X-direction plane passing through the center point.

[0032] The beneficial effects of the present invention are as follows: by simulating the surface temperature field characteristics of the tow in the high-temperature carbonization furnace during the heating process, the present invention can intuitively visualize the temperature change process of the tow during the carbon fiber production process, and then judge whether the heating capacity of the furnace chamber to the tow meets the process requirements, thereby providing support for subsequent structural optimization. The present invention can reduce experimental costs, optimize product design, shorten product development cycles, provide theoretical support for reducing energy consumption in carbon fiber production, and also provide a basis for related numerical simulation research. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of a three-dimensional model established in the simulation method of the present invention.

[0034] Figure 2 It is a flow chart of a three-dimensional simulation method of heating performance of a filament bundle in a high-temperature carbonization furnace based on a dynamic grid method of the present invention.

[0035] Figure 3It is a schematic diagram of the temperature distribution of the filament bundle during the heating process in the furnace chamber at any time of the present invention.

[0036] Figure 4 Schematic diagram of temperature distribution on the surface of the filament bundle of the present invention.

[0037] Figure 5 It is a schematic diagram of temperature distribution in the furnace cavity of the present invention. DETAILED DESCRIPTION

[0038] The method of the present invention is further described below in conjunction with the accompanying drawings and preferred specific embodiments of the present invention.

[0039] The present invention discloses a three-dimensional simulation method for heating performance of a wire bundle in a high-temperature carbonization furnace based on a dynamic grid method, which specifically includes the following steps: Figure 2 As shown in:

[0040] (1) Use the 3D CAD (Computer Aided Design) software SOLIDWORKS to establish a 3D simulation model of the high-temperature carbonization furnace muffle cavity fluid calculation domain and the heated filament bundle, such as Figure 1 and the related parameters set include: the geometry and geometric dimensions of the muffle cavity, the geometry and geometric dimensions of the inlet and outlet seals, the inlet dimensions of the inlet and outlet sealed nitrogen pipes, the outlet dimensions of the nitrogen pipe, and the geometry and geometric dimensions of the heated filament bundle.

[0041] (2) The high-temperature carbonization furnace muffle cavity fluid calculation domain and the three-dimensional simulation model of the heated filament bundle established in step (1) are respectively transferred to the Global Mesh Setup module of the ICEM software. In the Global Mesh Setup module, the Volume Meshing Parameters are set to Tetra / Mixed, and the high-temperature carbonization furnace muffle cavity fluid calculation domain and the three-dimensional simulation model of the heated filament bundle are meshed. The entire calculation domain uses an unstructured grid, that is, a tetrahedral grid. In order to ensure the accuracy of the flow field calculation results, the grid is encrypted near the wall surface of the filament bundle. According to the judgment standard of the grid quality in the ICEM software, the grid quality of the overall structure is guaranteed to be greater than 0.5. At the same time, in order to facilitate the subsequent setting of calculation conditions, the names of the inlet and outlet and wall boundaries of all three-dimensional simulation models are defined, including the filament bundle wall, the furnace cavity inlet and outlet, and the furnace cavity wall boundary names.

[0042] (3) The meshed fluid calculation domain and the three-dimensional simulation model of the heated filament bundle are transferred to the FLUENT module of the ANSYS software, and the boundary conditions are set.

[0043] (4) Set the temperature detection surface in the FLUENT module in the ANSYS software, and perform simulation calculations to obtain the results, which are used as indicators to determine the heating performance of the filament bundle in the high-temperature carbonization furnace; the process of setting the FLUENT module in the ANSYS software is as follows:

[0044] (4.1) Import the custom tow motion parameters compiled according to the process parameters in the User Defined option, control the motion state of the heated tow through UDF, and realize the motion process of the tow in the high-temperature carbonization furnace;

[0045] (4.2) In the General option, set the Gravitational Acceleration in the y direction to the preset value according to the actual situation, and set the time option to Transient transient heat transfer;

[0046] (4.3) Select Energy Equation in the Energy of Models option and select the laminar model in the Viscous Models option. In order to determine the state of airflow movement in the furnace cavity, the Reynolds number is introduced for description. The calculation formula of the Reynolds number is:

[0047]

[0048] Among them, v, ρ, μ are the velocity, density and viscosity coefficient of the fluid respectively, and d is the characteristic length; through the calculation of the Reynolds number, the turbulence model is selected as the laminar model;

[0049] (4.4) Select air and nitrogen in the Materials Fluid option section; establish the physical parameters of the tow in the Materials Solid option, including density, specific heat capacity, and thermal conductivity parameters;

[0050] (4.5) In the Cell Zone Conditions option, set Fluid1 to nitrogen and Fluid2 to oxygen; set Solid1 to tow;

[0051] (4.6) In the Boundary Conditions option, set the inlet boundary condition to Pressure-inlet, and set the Velocity Magnitude to the preset value according to actual requirements, set the Thermal option to udf tm-inlet, set the outlet boundary condition to Pressure-outlet, set one side of the wall to the convection heat transfer surface, UDF defines the comprehensive temperature value of the furnace wall air per hour, set the convection heat transfer coefficient to the preset value according to actual requirements, set other walls to adiabatic walls, and set the tow and gas contact surface to Coupled;

[0052] (4.7) In the Dynamic Mesh option, check the Activate Dynamic Mesh option, check the Smoothing and Remeshing options in the Mesh Methods option; define the motion zone in Dynamic Mesh Zones, select rigid wall under Zone Names, select Rigid Body in Type, and set the preview mesh motion in Preview Mesh Motion;

[0053] (4.8) After selecting Check Case, the calculation is performed. The calculation time is set according to the parameters in the actual project. The three-dimensional mathematical model of the full flow field calculation of the high-temperature carbonization furnace used for the calculation after selecting Check Case includes the continuity equation, momentum equation and energy equation, which are shown as follows:

[0054]

[0055] Where, ρ is fluid density; t is time; V is velocity vector, and u, v, w are the components of V in the x, y and z directions.

[0056] Navier-Stokes equation of momentum:

[0057]

[0058] Where μ is the dynamic viscosity, F b is the volume force on the infinitesimal element;

[0059] Energy conservation equation:

[0060]

[0061] Among them, C p —Specific heat capacity, T—temperature, k—fluid heat transfer coefficient, S T —viscous dissipation term;

[0062] During the specific implementation process, the center point of the three-dimensional simulation model of the high-temperature carbonization furnace muffle cavity fluid calculation domain is preferably selected as the detection surface, and the detection surface is the X-direction plane passing through the center point. The surface of the wire bundle is selected as the detection surface, and the detection surface is the X-direction plane passing through the center point.

[0063] (5) Under the same setting conditions, by setting different parameters for the high-temperature carbonization furnace muffle cavity fluid calculation domain and the three-dimensional simulation model of the heated filament bundle, and repeating steps (1)-(4) to perform multiple simulation calculations, the post-processing software CFD-POST is used to realize the visualization of the temperature field in the furnace cavity and the temperature field on the surface of the filament bundle during the heating process of the filament bundle from the temperature change cloud map of the detection surface, and the intuitive output result.

[0064] The post-processing software CFD-POST is used to visualize the temperature field in the furnace cavity and the temperature field on the surface of the tow during the tow heating process. Figure 4 , Figure 5 As can be seen from the figure, the three-dimensional calculation results not only fully meet the requirements in terms of accuracy, but also have various types of output data and more intuitive output results. Compared with the prior art, the three-dimensional simulation method of heating performance of a tow in a high-temperature carbonization furnace based on a dynamic grid method provided by the present invention has the following advantages:

[0065] (1) By introducing the motion state of the tow in the high-temperature carbonization furnace into the CFD calculation software, it is closer to reality.

[0066] (2) Regarding the heating performance of the wire bundle in the high-temperature carbonization furnace, the traditional method usually tests the performance of the wire bundle after heating. The present invention creatively uses the dynamic grid method to simulate the motion state of the wire bundle, and determines the heating capacity of the furnace through the cloud map of the temperature change on the surface of the wire bundle, so as to better measure the structural design.

[0067] (3) The temperature distribution characteristics of the fiber bundle surface at any time during its movement in the high-temperature carbonization furnace can be intuitively and dynamically calculated.

[0068] (4) It can be further used to study the heating performance of the high-temperature carbonization furnace on the filament bundle, thereby providing a reference for the design of the high-temperature carbonization furnace.

[0069] The present invention defines the movement law of the filament bundle through UDF, and by modifying the airflow velocity in the inlet boundary velocity-inlet, it is possible to obtain the change law of the surface temperature distribution of the filament bundle and the heat storage capacity in the muffle furnace under different filament bundle movement states. Analyzing the surface temperature distribution of the filament bundle, the temperature of the filament bundle gradually increases with the length of the filament bundle entering the furnace chamber, and the furnace chamber temperature is always kept constant. In summary, the surface temperature of the filament bundle gradually increases as it enters the furnace chamber, the filament bundle is heated, the furnace wall has a good heating effect, and its heat storage performance is excellent; Figure 3As shown in the figure, the temperature distribution diagram of the wire bundle in the furnace chamber during heating at any time is shown in the figure. Figure 4 The schematic diagram of the temperature distribution on the surface of the filament bundle shows that the temperature of the filament bundle surface increases gradually during the heating process, and the temperature distribution on the surface of the filament bundle is uniform; Figure 5 As shown, the temperature distribution diagram in the furnace cavity of the present invention shows that the temperature distribution in the muffle cavity is uniform, indicating that the airflow organization in the furnace cavity is reasonably distributed. In order to verify the simulation results, multiple simulations should be performed, and the experimental results should be compared and analyzed to obtain the optimal solution for the tow movement speed and the muffle furnace cavity heat storage performance.

[0070] The embodiments described in the present invention are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by engineers and technicians in this field should fall within the protection scope of the present invention. The technical contents for which protection is sought in the present invention have all been recorded in the claims.

Claims

1. A three-dimensional simulation method for heating performance of a tow in a high-temperature carbonization furnace based on a dynamic grid method, characterized in that The method comprises the following steps: (1) Use the 3D CAD software SOLIDWORKS to establish a 3D simulation model of the fluid calculation domain of the high-temperature carbonization furnace muffle cavity and the heated filament bundle; (2) The high-temperature carbonization furnace muffle cavity fluid calculation domain and the three-dimensional simulation model of the heated filament bundle established in step (1) are respectively transferred to the Global Mesh Setup module of the ICEM software. In the Global Mesh Setup module, the Volume Meshing Parameters are set to Tetra / Mixed for the meshing type. The high-temperature carbonization furnace muffle cavity fluid calculation domain and the three-dimensional simulation model of the heated filament bundle are meshed. The entire calculation domain uses an unstructured grid, and the grid is encrypted near the wall surface of the filament bundle. According to the grid quality judgment standard in the ICEM software, the grid quality of the overall structure is ensured to be greater than 0.

5. The names of the inlet and outlet and wall boundaries of all three-dimensional simulation models are defined, including the names of the filament bundle wall, the furnace cavity inlet and outlet, and the furnace cavity wall boundary. (3) The meshed fluid calculation domain and the three-dimensional simulation model of the heated tow are transferred to the FLUENT module of the ANSYS software, and the boundary conditions are set; (4) Set the temperature detection surface in the FLUENT module in the ANSYS software, and perform simulation calculations to obtain the results, which are used as indicators to determine the heating performance of the filament bundle in the high-temperature carbonization furnace; the process of setting the FLUENT module in the ANSYS software is as follows: (4.1) Import the custom tow motion parameters compiled according to the process parameters in the User Defined option, control the motion state of the heated tow through UDF, and realize the motion process of the tow in the high-temperature carbonization furnace; (4.2) In the General option, set the Gravitational Acceleration in the y direction to the preset value according to the actual situation, and set the time option to Transient transient heat transfer; (4.3) Select Energy Equation in the Energy of Models option and select the laminar model in the Viscous Models option. In order to determine the state of airflow movement in the furnace cavity, the Reynolds number is introduced for description. The calculation formula of the Reynolds number is: Among them, v, ρ, μ are the velocity, density and viscosity coefficient of the fluid respectively, and d is the characteristic length; through the calculation of the Reynolds number, the turbulence model is selected as the laminar model; (4.4) Select air and nitrogen in the Materials Fluid option section; establish the physical parameters of the tow in the Materials Solid option, including density, specific heat capacity, and thermal conductivity parameters; (4.5) In the Cell Zone Conditions option, set Fluid1 to nitrogen and Fluid2 to oxygen; set Solid1 to tow; (4.6) In the Boundary Conditions option, set the inlet boundary condition to Pressure-inlet, and set the Velocity y Magnitude to the preset value according to actual requirements, set the Thermal option to udftm-inlet, set the outlet boundary condition to Pressure-outlet, set one side of the wall to the convection heat transfer surface, UDF defines the comprehensive temperature value of the furnace wall air per hour, set the convection heat transfer coefficient to the preset value according to actual requirements, set other walls to adiabatic walls, and set the tow and gas contact surface to Coupled; (4.7) In the DynamicMesh option, check the Activate Dynamic Mesh option, check the Smoothing and Remeshing options in the MeshMethods option; define the motion area in DynamicMeshZones, select rigidwall under Zonee Names, select RigidBody in Type, and set the preview mesh motion in PreviewMesh Motion; (4.8) After selecting CheckCase, the calculation is performed. The calculation time is set according to the parameters in the actual project. The three-dimensional mathematical model of the full flow field calculation of the high-temperature carbonization furnace used for the calculation after selecting CheckCase includes the continuity equation, momentum equation and energy equation, which are shown as follows: Where, ρ is fluid density; t is time; V is velocity vector, where u, v, w are the components of V in the x, y and z directions; Navier-Stokes equation of momentum: Where μ is the dynamic viscosity, F b is the volume force on the infinitesimal element; Energy conservation equation: Among them, C p —Specific heat capacity, T—temperature, k—fluid heat transfer coefficient, S T —viscous dissipation term; (5) Under the same setting conditions, by setting different parameters for the high-temperature carbonization furnace muffle cavity fluid calculation domain and the three-dimensional simulation model of the heated filament bundle, and repeating steps (1)-(4) to perform multiple simulation calculations, the post-processing software CFD-POST is used to realize the visualization of the temperature field in the furnace cavity and the temperature field on the surface of the filament bundle during the heating process of the filament bundle from the temperature change cloud map of the detection surface, and the intuitive output result.

2. The three-dimensional simulation method of heating performance of a tow in a high-temperature carbonization furnace based on a moving grid method according to claim 1, characterized in that: The parameters set for the three-dimensional simulation model of the high-temperature carbonization furnace muffle cavity fluid calculation domain and the heated filament bundle in step (1) include: the geometry and geometric dimensions of the muffle cavity, the geometry and geometric dimensions of the inlet and outlet seals, the inlet dimensions of the inlet and outlet sealed nitrogen pipes, the outlet dimensions of the nitrogen pipe, and the geometry and geometric dimensions of the heated filament bundle.

3. The three-dimensional simulation method of heating performance of a tow in a high-temperature carbonization furnace based on a moving grid method according to claim 1, characterized in that: In step (4), the center point of the three-dimensional simulation model of the high-temperature carbonization furnace muffle cavity fluid calculation domain is selected as the detection surface, and the detection surface is the X-direction plane passing through the center point. The surface of the wire bundle is selected as the detection surface, and the detection surface is the X-direction plane passing through the center point.

Images