COMSOL-based thermal deformation analysis method for QBH indirect water-cooling structure

Abstract

The application relates to a COMSOL-based thermal deformation analysis method of a QBH indirect water cooling structure and belongs to the technical field of finite element analysis methods of optical mechanical structures. The application utilizes NX three-dimensional drawing software to establish a three-dimensional model of the QBH indirect water cooling structure, and imports the geometric model through a COMSOL software "CAD import" module, so that the establishment time of the finite element model is greatly saved; through a COMSOL "thermal expansion" structure mechanics-solid heat transfer multi-physical field coupling interface, a deformation analysis method under the influence of thermal stress of the QBH indirect water cooling structure is provided; the "material Switch" and "parameter scanning" functions are adopted to analyze that, when the QBH indirect water cooling structure works in a high-temperature environment, thermal stress generated by different metal materials extrudes the deformation of the quartz end cap, and the thermal stress change condition of the quartz end cap under the temperature rise state of cooling water, so that reliable theoretical data and selection guidance are provided for QBH indirect water cooling packaging design.

Description

Technical Field

[0001] This invention belongs to the technical field of finite element analysis methods for optical and mechanical structures, and relates to a thermal deformation analysis method for QBH indirect water-cooled structures based on COMSOL. Background Technology

[0002] An indirect water-cooled QBH (quartz block head) is encapsulated by a quartz end cap and an indirect water-cooling mechanical structure, used for outputting high-power fiber lasers. The indirect water-cooling structure uses a metal sleeve to isolate the cooling water from the quartz end cap and the transmission fiber, effectively preventing impurities in the cooling water from adsorbing onto the transmission fiber, thus avoiding problems such as damage to the fiber laser output structure due to heat absorption by impurities. The indirect water-cooling metal sleeve and the quartz end cap are in direct contact, and their material properties, such as thermal expansion coefficients, Young's modulus, and density, differ significantly. When operating in high-temperature environments, the QBH structure generates thermal stress and undergoes inconsistent deformation, causing compression of the quartz end cap. In severe cases, thermal cracking can occur, damaging the quartz end cap and affecting fiber laser output or even the entire fiber laser system. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] The technical problem to be solved by this invention is to propose a deformation analysis method based on COMSOL for QBH indirect water-cooled structures under the influence of thermal stress, so as to provide a theoretical basis for QBH indirect water-cooled packaging design and guidance for packaging material selection.

[0005] (II) Technical Solution

[0006] To address the aforementioned technical problems, this invention provides a COMSOL-based method for thermal deformation analysis of QBH indirect water-cooled structures, comprising the following steps:

[0007] Step 1: Perform 3D modeling of the QBH indirect water-cooling structure. Use NX drawing software to design the 3D model of the QBH indirect water-cooling structure.

[0008] Step 2: Complete the geometric simplification of the QBH indirect water-cooling structure. This involves importing the three-dimensional model of the QBH indirect water-cooling structure into the finite element analysis software COMSOL, and completing the geometric simplification process in the COMSOL model preprocessing.

[0009] Step 3: Complete the definition of physical parameters of QBH indirect water-cooled structure materials, define the quartz end cap region as fused silica material, and define the cooling jacket region as metal material, including stainless steel 316, oxygen-free copper TU2, titanium alloy TC4 and aluminum alloy 2124.

[0010] Step 4: Add solid mechanics physics fields and set physical conditions such as initial values, linear elastic material domain, free boundary, fixed constraint boundary, contact pair boundary, and symmetric boundary;

[0011] Step 5: Add a solid heat transfer physics field and set physical conditions such as solid domain, initial temperature value, temperature boundary, heat flux boundary, symmetry boundary and insulation boundary;

[0012] Step 6: Add a thermal expansion coupling physics field, and set the heat transfer and structural coupling interface, thermal expansion properties, and heat source;

[0013] Step 7: Perform mesh generation, setting both the quartz end cap region and the metal structure region to free tetrahedral mesh, and then add corner refinement to avoid mesh inversion during the calculation process;

[0014] Step 8: Add steady-state studies for multiphysics coupling analysis of structural stress-deformation-temperature;

[0015] Step 9: Post-process the research results and perform data analysis on the stress, deformation, contact force, and temperature distribution of the quartz end cap of the indirect water-cooled QBH structure.

[0016] Furthermore, in step three, in order to compare and analyze the differences in thermal stress-deformation-temperature distribution of different materials in the indirect water-cooled packaging structure under high-temperature working environment, the materials of the indirect water-cooled packaging structure are set to four metals respectively through "Material Switch": stainless steel 316, oxygen-free copper TU2, titanium alloy TC4, and aluminum alloy 2124, to guide the selection of materials for the QBH indirect water-cooled packaging structure.

[0017] Furthermore, in step five, in order to analyze the differences in thermal stress-deformation-temperature distribution of the QBH indirect water-cooled structure when environmental changes such as an increase in cooling water temperature are performed, the "parameter scan" function is used to analyze the influence of a series of cooling water temperatures on the multi-physics coupling results of thermal expansion, so as to observe the deformation differences of the quartz end cap under the condition of circulating water temperature rise when the QBH is working in a high-temperature environment.

[0018] Furthermore, in step four, the contact pairs are added at the "Model Definition" section. The contact surface between the cooling jacket and the quartz end cap is the source boundary, and the contact surface between the quartz end cap and the cooling jacket is the target boundary. The contact method is augmented Lagrangian, and the initial contact pressure is preset to 0 N / m. 2 .

[0019] Further, in step five, both the cooling domain and the quartz end cap domain are set as "solid domains," with initial temperatures set to T_silica and T_metal, respectively. Temperature boundaries T_fused and T_output are added for the fused and output ends of the quartz end cap, respectively, and "heat flux, thermal insulation, symmetry, and thermal contact" boundaries are set according to the operating conditions. Specifically, the cooling jacket water-cooled environment simulates the circulating water heat transfer mechanism using the COMSOL heat flux boundary "external forced convection - cylinder flow," with the circulating water temperature set to T_water. The symmetry and thermal contact boundaries are consistent with the solid mechanics physical field settings. The thermal contact boundary can define the contact surface properties using "surface roughness, average roughness height" and "surface roughness, average roughness slope." Other air contact surfaces and geometrically simplified surfaces have almost no heat convection or heat conduction mechanisms and are all defined as thermally insulating.

[0020] Furthermore, in step eight, the stress, deformation, contact force, and temperature distribution of the quartz end cap of the indirect water-cooled QBH structure are calculated using the "Material Scan" and "Parameter Scan" functions under different cooling jacket materials and circulating water temperatures. Specifically, the "Material Scan" selects the "Material Switch" combination, and the "Parameter Scan" selects the parameter "T_water" and sets the calculation step Range to (20, 0.5, 27)℃ to obtain the finite element model analysis results of the indirect water-cooled QBH under a series of circulating water temperatures.

[0021] Furthermore, in step nine, firstly, if the circulating water temperature is 25℃ and the metal material is stainless steel 316, draw the stress, contact force, temperature distribution and deformation displacement diagrams of the quartz end cap and cooling jacket.

[0022] Furthermore, by calling "Research / Parameter Resolution" and using "Boundary Probe - Maximum Value", the maximum values ​​of "volume stress" and "surface contact force" of the quartz end cap were calculated. By using "Boundary Probe - Average Value / Maximum Value", the average deformation and maximum deformation of the contact surface of the quartz end cap were calculated. By comparing and analyzing the effects of different metal materials on the encapsulation of the quartz end cap, it was found that the cooling jacket material of the QBH indirect water cooling structure is selected as stainless steel 316 or titanium alloy TC4.

[0023] The present invention also provides a system for implementing the method.

[0024] The present invention also provides an application of the method in the field of finite element analysis of optical mechanical structures.

[0025] The present invention also provides an application of the system in the field of finite element analysis methods for optical and mechanical structures.

[0026] (III) Beneficial Effects

[0027] This invention utilizes NX 3D drawing software to establish a 3D model of the QBH indirect water-cooled structure, and imports the geometric model through the "CAD Import" module of COMSOL software, greatly saving the time of finite element model establishment. Through the COMSOL "thermal expansion" structural mechanics-solid heat transfer multiphysics coupling interface, a deformation analysis method for the QBH indirect water-cooled structure under the influence of thermal stress is provided. Using the "Material Switch" and "Parameter Scan" functions, the extrusion deformation of the quartz end cap caused by the thermal stress generated by different metal materials when the QBH indirect water-cooled structure is working in a high-temperature environment is obtained, as well as the change of thermal stress of the quartz end cap under the cooling water temperature rise state, providing reliable theoretical data and selection guidance for the QBH indirect water-cooled packaging design. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating the finite element model workflow of the present invention.

[0029] Figure 2 This is a three-dimensional structural diagram of the QBH indirect water-cooling structure of the present invention, where a is a left view and b is a cross-sectional view;

[0030] Figure 3 For the geometric simplification of the QBH indirect water-cooling structure of the present invention, a is a left view; b is a cross-sectional view;

[0031] Figure 4 This is a geometric domain mesh partitioning diagram of the present invention;

[0032] Figure 5 These are the steady-state study results of this invention;

[0033] Figure 6 This is a deformation displacement distribution diagram of the QBH indirect water-cooled structure of the present invention;

[0034] Figure 7 Stress and contact force analysis diagram of the quartz end cap under the cooling jacket of different materials in this invention;

[0035] Figure 8 This is an analysis diagram of the average and maximum deformation of the quartz end cap under the cooling jacket of different materials according to the present invention. Detailed Implementation

[0036] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0037] like Figure 1 The diagram illustrates the workflow of a COMSOL-based QBH indirect water-cooled structure thermal deformation analysis method according to the present invention. Detailed steps are as follows:

[0038] Step 1: Create a 3D model of the QBH indirect water-cooling structure. Use NX drawing software to create a 3D model of the QBH indirect water-cooling structure, such as... Figure 2 As shown;

[0039] Step Two: Perform geometric simplification of the QBH indirect water-cooling structure. Import the 3D model of the QBH indirect water-cooling structure into the finite element analysis software COMSOL. In the COMSOL software preprocessing, perform structural simplification of the 3D model to reduce the number of meshes and the amount of finite element calculations, such as... Figure 3 As shown, unnecessary geometric features such as cooling chambers and plugs are removed through operations such as "delete face" and "delete solid". The symmetrical parts of the 3D model are preserved by adding "cuboid" geometry and "subtraction" Boolean operation, and the cooling sleeve and quartz end cap are formed into an assembly. In addition, the geometric structure features are simplified through virtual operations such as "form composite surface", "remove details" and "ignore edges" to improve the efficiency of subsequent calculations.

[0040] Step 3: Define the physical parameters of the geometric domain materials. Define the quartz end cap domain as fused silica material, and the cooling jacket domain as stainless steel 316, titanium alloy TC4, oxygen-free copper TU2, and aluminum alloy 2124. Assign material properties to the cooling jackets using the "Material Switch". The specific parameters (@temperature 298.15K) are shown in Table 1.

[0041] Table 1. Material Parameters of QBH Cooling Jacket

[0042]

[0043] Step 4: Set up the solid mechanics physics field. Set both the cooling jacket region and the quartz end cap region to "linear elastic material," with initial values ​​of 0 for the displacement field and structural velocity field. Set boundary conditions as "fixed constraint, symmetry, contact pair, and free." Note that the contact pair is added in the "model definition" section. The contact surface between the cooling jacket and the quartz end cap is the source boundary, and the contact surface between the quartz end cap and the cooling jacket is the target boundary. The contact method is augmented Lagrangian, and the initial contact pressure is preset to 0 N / m. 2 It has been verified that the initial contact pressure has no effect on the steady-state study results.

[0044] Step 5: Set up the solid-state heat transfer physics field. Set both the cooling domain and the quartz end cap domain as "Solid Domain," with initial temperatures set to T_silica and T_metal, respectively. Add temperature boundaries T_fused and T_output for the fused and output ends of the quartz end cap, setting "Heat Flux, Thermal Insulation, Symmetry, and Thermal Contact" boundaries according to the operating conditions. Specifically, the cooling jacket water-cooled environment simulates the circulating water heat transfer mechanism using the COMSOL heat flux boundary "External Forced Convection - Flow Around a Cylindrical Circulation," with the circulating water temperature set to T_water. The symmetry and thermal contact boundaries are consistent with the solid-state physics field settings. The thermal contact boundary can be defined by "Surface Roughness, Average Roughness Height" and "Surface Roughness, Average Roughness Slope." Other air contact surfaces and geometrically simplified surfaces have almost no heat convection or conduction mechanisms and are defined as thermally insulating. Table 2 shows the temperature setting parameters for the physical field of solid heat transfer. It is worth noting that the material parameters in Table 1 are taken from a room temperature of 25℃. Therefore, the reference temperature of the finite element model is 25℃, which represents the temperature value when the QBH indirect water-cooled structure has no thermal deformation.

[0045] Table 2 Temperature parameters of the finite element model of the QBH indirect water-cooled structure

[0046]

[0047] Step 6: Add a thermal expansion multiphysics field. The heat transfer interface comes from the "Solid Heat Transfer" physics field, and the structural interface comes from the "Solid Mechanics" physics field, for structural thermal coupling analysis.

[0048] Step 7: Mesh the area. Set both the cooling sleeve region and the quartz end cap region to "Free Tetrahedral Mesh" and add a "Corner Refinement" mesh generator. For example... Figure 4 As shown, the mesh size of the quartz end cap domain is significantly smaller than that of other geometric domains, thus avoiding errors such as mesh reversal during finite element calculations.

[0049] Step 8: Add steady-state study. Using the "Material Scan" and "Parameter Scan" functions, calculate the stress, deformation, contact force, and temperature distribution of the quartz end cap of the indirect water-cooled QBH structure under different cooling jacket materials and circulating water temperatures. Specifically, select the "Material Switch" combination for "Material Scan," and select the parameter "T_water" for "Parameter Scan," setting the calculation step Range to (20, 0.5, 27)℃. This yields the finite element model analysis results of the indirect water-cooled QBH under a series of circulating water temperatures.

[0050] Step Nine: Post-processing of Research Results. First, taking a circulating water temperature of 25℃ and stainless steel 316 as an example, plot the stress, contact force, temperature distribution, and deformation displacement diagrams of the quartz end cap and cooling jacket, as shown below. Figure 5 and Figure 6 As shown.

[0051] Depend on Figure 5 It is known that the circulating water forced convection cooling effectively cooled the QBH structure, and the temperature of the molten end of the quartz end cap stabilized at around 27℃, which is within the safe temperature range for the welding test. There is obvious stress inside the quartz end cap, and the surface contact force is concentrated at the cylindrical edge of the quartz end cap. The stress of the cooling jacket is mainly distributed in the area near the contact surface with the quartz end cap, and the stress distribution is the greatest at the junction of its output end and the inner side, which causes compression to the quartz end cap. Figure 6 The original image (i.e., 1x view) and 500x view of the deformation displacement of the quartz end cap are shown. The amount of deformation displacement of the quartz end cap due to the compression of the cooling jacket is small and invisible to the naked eye. The internal stress is released to the output end of the end cap, and the output end area is prone to cracking.

[0052] Furthermore, by calling "Research / Parameter Resolution" and using "Boundary Probe - Maximum Value," the maximum values ​​of the "volume stress" and "surface contact force" of the quartz end cap are calculated. Then, by using "Boundary Probe - Average / Maximum Value," the average and maximum deformation of the quartz end cap contact surface are calculated. The influence of different metal materials on the encapsulation of the quartz end cap is then compared and analyzed. Figure 7 and Figure 8 As shown. By Figure 7 It is known that, compared to oxygen-free copper TU2 and aluminum alloy 2124, stainless steel 316 and titanium alloy TC4 encapsulation result in lower stress on the quartz end caps and a slower rate of increase with temperature; while stainless steel 316 exhibits the highest contact force, and titanium alloy TC4 exhibits the lowest contact force. The contact force caused by these two metals increases with temperature much less rapidly than the other two materials. Figure 8 It is known that within the temperature range of 20–27℃, the average deformation displacement change of both 316 stainless steel and TC4 titanium alloy is approximately 0.2 μm, with a rate of change far lower than that of the other two materials, and the maximum value does not exceed 0.8 μm. The deformation caused by stress and contact force is relatively small. Based on the above analysis, 316 stainless steel and TC4 titanium alloy are the preferred materials for the cooling jacket of the QBH indirect water-cooled structure, with TC4 titanium alloy being the best choice.

[0053] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A COMSOL-based thermal deformation analysis method for a QBH indirect water-cooling structure, characterized in that, The method comprises the following steps: Step one: three-dimensional modeling of the QBH indirect water cooling structure is performed, and NX drawing software is used to design a three-dimensional model of the QBH indirect water cooling structure; Step two: geometric simplification of the QBH indirect water cooling structure is completed, wherein the three-dimensional model of the QBH indirect water cooling structure is imported into finite element analysis software COMSOL, and geometric structure simplification is completed in COMSOL model preprocessing; Step three: the definition of material physical parameters of the QBH indirect water cooling structure is completed, the quartz end cap domain is defined as a fused quartz material, and the cooling sleeve domain is defined as a metal material, including stainless steel 316, oxygen-free copper TU2, titanium alloy TC4 and aluminum alloy 2124; Step four: a solid mechanics physical field is added, and initial values, linear elastic material domains, free boundaries, fixed constraint boundaries, contact pair boundaries and symmetric boundary physical conditions are set; Step five: a solid heat transfer physical field is added, and solid domains, temperature initial values, temperature boundaries, heat flux boundaries, symmetric boundaries and insulation boundaries are set; Step six: a thermal expansion coupling physical field is added, and a heat transfer and structure coupling interface, thermal expansion attribute and heat source are set; Step seven: mesh division is performed, and the quartz end cap domain and the metal structure domain are both set as free tetrahedral mesh division, and then corner refinement is added to avoid mesh inversion in the calculation process; Step eight: a steady-state study is added, which is used for structure stress-deformation-temperature multi-physical field coupling analysis; Step nine: research result post-processing is performed, and data analysis is performed on the stress, deformation, contact force and temperature distribution of the quartz end cap of the indirect water cooling QBH structure.

2. The method of claim 1, wherein, In step three, in order to compare and analyze the thermal stress-deformation-temperature distribution differences of different materials of the indirect water cooling packaging structure in a high temperature working environment, the materials of the indirect water cooling packaging structure are set as stainless steel 316, oxygen-free copper TU2, titanium alloy TC4 and aluminum alloy 2124 respectively through "material Switch" for comparative analysis, so as to guide the material selection of the QBH indirect water cooling packaging structure.

3. The method of claim 1, wherein, In step five, in order to analyze the thermal stress-deformation-temperature distribution differences of the QBH indirect water cooling structure when the environment changes, such as the increase of cooling water temperature, a series of cooling water temperatures are analyzed by using the "parameter scanning" function to analyze the influence of the thermal expansion multi-physical field coupling results, so as to observe the deformation differences of the quartz end cap under the condition of the increase of the circulating water temperature when the QBH works in a high temperature environment.

4. The method of claim 1, wherein, In step four, the contact pair is added by "Model Definition", the contact surface of the cooling jacket and the quartz end cap is the source boundary, the contact surface of the quartz end cap and the cooling jacket is the target boundary, the contact method is the augmented Lagrange, and the initial value of the contact pressure is preset as 0 N / m 2 .

5. The method of claim 1, wherein, In step five, the cooling zone and the quartz end cap zone are both set as "solid zone", and the initial temperature values are set as T_silica and T_metal, respectively; the quartz end cap fused end and the output end "temperature" boundary T_fused and T_output are added, and the "heat flux, heat insulation, symmetry, and thermal contact" boundary is set according to the working condition; wherein the cooling jacket water cooling environment is simulated by the COMSOL heat flux boundary "external forced convection-cylinder flow" to simulate the circulating water heat transfer mechanism, and the circulating water temperature is set as T_water; the symmetry and thermal contact boundary is consistent with the solid mechanics physical field setting, and the thermal contact pair boundary can define the contact surface attribute through "surface roughness, roughness average height" and "surface roughness, roughness average slope"; other air contact surfaces, geometric simplification surfaces have almost no heat convection and heat conduction mechanism, and are defined as heat insulation.

6. The method of claim 1, wherein, In step eight, the stress, deformation, contact force, and temperature distribution of the quartz end cap of the indirect water-cooled QBH structure under different cooling jacket materials and circulating water temperatures are calculated through the "material scanning" and "parameter scanning" functions; wherein the "material scanning" selects the "material Switch" combination, the "parameter scanning" selects the parameter "T_water" and sets the calculation step Range(20, 0.5, 27) ℃, and the analysis results of the indirect water-cooled QBH finite element model under a series of circulating water temperatures are obtained.

7. The method of claim 1, wherein, In step nine, first, if the circulating water temperature is 25 ℃ and the metal material is stainless steel 316, the stress, contact force, temperature distribution, and deformation displacement of the quartz end cap and the cooling jacket are plotted; Further, the "research / parameterized solution" is called, the "boundary probe-maximum value" is calculated to obtain the maximum values of the "body stress" and the "surface contact force" of the quartz end cap, and the "boundary probe-average value / maximum value" is calculated to obtain the average deformation and the maximum deformation of the quartz end cap contact surface, the influence of different metal materials on the packaging of the quartz end cap is compared and analyzed, and it is found that the cooling jacket material metal of the indirect water-cooled QBH structure is selected as stainless steel 316 or titanium alloy TC4.

8. A system for implementing the method of any one of claims 1 to 7.

9. The use of the method of any one of claims 1 to 7 in the technical field of finite element analysis methods of optical mechanical structures.

10. The use of the system of claim 8 in the technical field of finite element analysis methods of optical mechanical structures.

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