A method for optimizing the non-uniform layout of adjustable heating element assembly structures

Abstract

This invention provides a non-uniform layout optimization method for an adjustable heating element assembly structure, relating to the field of vacuum furnace technology. This invention uses a neural network to optimize the heating element layout parameters under specified objective functions, including but not limited to furnace temperature uniformity, workpiece temperature uniformity, maximum energy efficiency ratio within the furnace, and workpiece surface heat flux density. This method can obtain, under the conditions of satisfying the physical boundary conditions of the vacuum furnace and the objective function, the optimal heating element layout parameters for a vacuum sintering furnace, satisfying both the objective function and boundary conditions, can be obtained. After obtaining the optimal heating element layout parameters satisfying the objective function and boundary conditions through the neural network-based non-uniform layout parameter optimization method, the length of the heating element can be dynamically adjusted through the adjustable heating element assembly.

Description

Technical Field

[0001] This invention relates to the field of vacuum furnace technology, and more specifically to a method for optimizing the non-uniform layout of a heating element assembly structure with adjustable layout. Background Technology

[0002] Silicon carbide is a crucial semiconductor device widely used in aerospace, integrated circuits, and other fields. The fabrication of silicon carbide workpieces is primarily achieved through reaction sintering. The production process involves multiple steps, including mixing, pressing, dewaxing and pre-firing, placing the silicon cake, vacuum sintering, polishing to remove silicon, drying, and sintering the sample. Vacuum sintering is particularly critical, consuming approximately 60% of the energy in the entire process.

[0003] The main vacuum sintering equipment currently is the vacuum sintering furnace, in which the heating chamber is the sintering site for silicon carbide workpieces. The heating chamber provides a uniform temperature environment for the silicon carbide workpieces, which is conducive to the densification of silicon carbide workpieces by sintering at a lower temperature and in a shorter time, thereby avoiding the adverse effects on the material such as high-temperature decomposition and abnormal grain growth.

[0004] The layout of the heating elements in the heating chamber directly affects the temperature distribution inside the furnace. The temperature distribution inside the furnace and the distribution characteristics of the heating elements directly affect the quality of the silicon carbide workpieces sintered. Therefore, the layout design of the heating elements in the sintering furnace is an important prerequisite for ensuring high-quality silicon carbide workpieces sintered in a vacuum sintering furnace.

[0005] Regarding the aforementioned technologies, existing technologies typically arrange heating elements at certain intervals in a rectangular, evenly distributed pattern around the vacuum furnace cavity, forming a group of heating elements. These heating element groups are then symmetrically installed within the vacuum sintering furnace while maintaining a certain spacing. However, due to the presence of pores, cracks, and limitations in sealing technology near the furnace doors, significant heat loss occurs near the doors. This results in a large temperature difference between the area near the doors and the interior of the furnace, leading to poor temperature uniformity. Furthermore, the space near the doors cannot be effectively used for the reaction sintering of silicon carbide workpieces, resulting in wasted furnace space. This limits the output of the vacuum sintering process and the utilization of the vacuum sintering furnace's thermal efficiency. Additionally, the layout of the heating element groups is usually not adjustable due to limitations imposed by the conductive supports and electrode leads.

[0006] Chinese patent CN114492079A proposes an optimization method for silicon carbide vacuum sintering furnaces based on computational heat transfer simulation. It establishes a model of thermal radiation and heat conduction during the heating process of the vacuum sintering furnace based on its body parameters. Computational heat transfer simulation is then performed to optimize the original furnace type. However, when faced with a large amount of data, including different furnace types and numerous different heating element layout parameters, the Ansys Fluent computational model requires re-meshing for each parameter adjustment and a significant amount of time for iterative calculations, resulting in extremely slow computation speed and high time complexity.

[0007] Chinese patent CN203782277U proposes a birdcage-shaped annular graphite heating element with multiple slots for a high-temperature vacuum furnace. Because the heating element layout parameters are fixed and cannot be adjusted, it is impossible to adjust the heating element layout parameters according to actual conditions when facing situations such as poor temperature uniformity within the furnace after installation, or when other desired performance indicators cannot be achieved. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to propose a non-uniform layout optimization method for adjustable heating element assembly structures, comprising:

[0009] Step 1: Simulate the heating process of the workpiece in the vacuum sintering furnace based on four sets of heating elements to obtain temperature data. The temperature data includes the average temperature inside the vacuum furnace, the average temperature of multiple cross sections of the heating chamber in the vacuum furnace, the average temperature of the entire workpiece, the temperature of each temperature measurement point on the workpiece, and the initial temperature of the workpiece.

[0010] Step 2: Calculate the furnace temperature uniformity σ, sintered workpiece temperature anomaly ε, maximum furnace energy efficiency ratio η, and workpiece surface heat flux density Q / A based on temperature data; use the furnace temperature uniformity σ, sintered workpiece temperature anomaly ε, maximum furnace energy efficiency ratio η, and workpiece surface heat flux density Q / A as output samples, and use the layout parameters of the four sets of heating elements as input samples. The output samples and input samples constitute training samples, and multiple training samples constitute a training sample set.

[0011] Step 3: Train the CNN neural network model based on the training sample set to obtain a performance parameter optimization model;

[0012] Step 4: Based on the preset range of values ​​for the layout parameters of the four sets of heating elements, an initial population containing 10,000 layout parameters is randomly generated using real number encoding. A chaotic genetic algorithm is used, with a chaotic factor added, and the chaotic migration ratio and iteration number set to screen the initial population to obtain the target population.

[0013] Step 5: Based on the performance parameter optimization model, determine one or more target parameters in the target population, obtain the layout parameters corresponding to the target parameters, and adjust the layout of the four sets of heating elements in the adjustable heating element group structure based on the layout parameters of the four sets of heating elements.

[0014] Optionally, in step 2, the furnace temperature uniformity σ, the sintered workpiece temperature anomaly ε, the furnace maximum energy efficiency ratio η, and the workpiece surface heat flux density Q / A are calculated based on the temperature data using the following formulas:

[0015]

[0016] in, T represents the average temperature inside the vacuum furnace. i is the average temperature of the i-th cross-section of the heating chamber in the vacuum furnace, and n is the number of cross-sections;

[0017]

[0018] in, The temperature represents the average temperature of the entire workpiece, where N represents the number of temperature measurement points taken on the workpiece, and T represents the average temperature of the entire workpiece. j This represents the temperature at the j-th temperature measurement point on the workpiece;

[0019]

[0020] Among them, c g This indicates the specific heat capacity of the workpiece. T represents the average temperature of the entire workpiece, T0 represents the initial temperature of the workpiece, and ρ represents the average temperature of the entire workpiece. g V represents the density of the workpiece. g The volume of the workpiece is represented by P, and the furnace heating power is represented by t. s Indicates heating time;

[0021] Q / A = P1 / A;

[0022] Where P1 is the heat power absorbed or dissipated by the workpiece, and A is the area of ​​the workpiece surface.

[0023] Optionally, in step 3, during model training of the CNN neural network model, the parameters of the CNN neural network model are updated using the energy equation and the DO radiation model equation for discrete coordinates. The energy equation is:

[0024]

[0025] Where ρ is the density of the radiating material. Here, is the Hamiltonian operator, E is the specific total energy (i.e., the total energy per unit mass), t is time, U is velocity (U = 0 in the solid domain), and q is the heat flux. The work done by viscous stress is represented by p, where p is the pressure and S is the work term. e For other lost heat, g is the acceleration due to gravity;

[0026] The equations for the DO radiation model in discrete coordinates are:

[0027]

[0028] Where σ is the Stefan-Boltzman constant; σ s is the scattering coefficient; a is the absorption coefficient; n is the refractive index; r is the Cartesian coordinate of the radiation source in space (x, y, z); s is the unit vector of the radiation direction of the radiation source (n x n y n z ); I is the radiation intensity, dΩ′ is a spherical infinitesimal element; s' is a unit vector in another radiation direction. Let T be the incident radiation intensity and T be the temperature.

[0029] Optionally, in step 5, based on the performance parameter optimization model, one or more target parameters are determined in the target population, including:

[0030] For each layout parameter in the target population, the layout parameter is input into the performance parameter optimization model to obtain its corresponding temperature parameters. The temperature parameters include furnace temperature uniformity σ, sintered workpiece temperature anomaly ε, furnace maximum energy efficiency ratio η, and workpiece surface heat flux density Q / A, thereby obtaining the target parameters corresponding to all layout parameters. Among all temperature parameters, one or more target parameters are selected. The temperature uniformity σ among the target parameters is the minimum value of all temperature uniformity σ, the sintered workpiece temperature anomaly ε is the maximum value of all sintered workpiece temperature anomaly ε, the furnace maximum energy efficiency ratio η is the maximum value of all furnace maximum energy efficiency ratio η, and the workpiece surface heat flux density Q / A is the maximum value of all workpiece surface heat flux density Q / A.

[0031] Optionally, the adjustable heating element assembly structure consists of four heating element assemblies, each heating element assembly including four sub-heating element assemblies, each sub-heating element assembly including multiple adjustable conductive supports and multiple adjustable heating elements, one adjustable support being connected to the first end of the adjustable heating element, another adjustable support being connected to the second end of the adjustable heating element, and the multiple adjustable heating elements being parallel.

[0032] Optionally, the adjustable heating element group structure is an adjustable parallel heating element group structure, which consists of four heating element groups. Each heating element group includes four sub-heating element groups, and each sub-heating element group includes two adjustable conductive support groups, multiple adjustable heating elements, and multiple heating element conductive support fixing devices.

[0033] The adjustable conductive support assembly includes two adjustable conductive supports, two conductive support fixing devices, four conductive support fixing bolts, two conductive support fixing seats, and four conductive support fixing rings; the two adjustable conductive supports are parallel, the two conductive support fixing devices are parallel, the two adjustable conductive supports are above the two conductive support fixing devices, and there is a gap between the two adjustable conductive supports and the two conductive support fixing devices.

[0034] The adjustable conductive support includes an electrode connector and a conductive support body. The conductive support body is a long rectangular parallelepiped with protruding plate-shaped rectangular parallelepipeds at both ends. Each plate-shaped rectangular parallelepiped has a threaded hole with internal threads. One plane of the length and width of the conductive support body is serrated, and the planes of the length and height of the conductive support body are connected to the electrode connector. The electrode connector is a plate-shaped rectangular parallelepiped with holes penetrating the centers of two parallel planes of length and width. The planes of the length and height of the electrode connector are connected to the planes of the length and height of the conductive support body.

[0035] The conductive support fixing device is a long rectangular prism. The two planar ends of the width and height of the conductive support fixing device are designed with protruding plate-shaped rectangular prisms. The plate-shaped rectangular prisms are designed with threaded holes for the conductive support fixing device. The threaded holes for the conductive support fixing device are designed with internal threads. One plane of the length and width of the conductive support fixing device is serrated.

[0036] The conductive support holder is a long rectangular prism, and the conductive support holder is designed with a long hole that runs through two planes, the length and the width.

[0037] The conductive support fixing bolt is designed with external threads, and the conductive support fixing ring is designed with internal threads. The external threads of the conductive support fixing bolt and the internal threads of the conductive support fixing ring mesh.

[0038] The conductive bracket fixing bolt engages with the internal thread of a threaded hole in the conductive bracket, the conductive bracket fixing bolt engages with the hole in the conductive bracket fixing seat, and the conductive bracket fixing bolt engages with the internal thread of the threaded hole in the conductive bracket fixing device.

[0039] The adjustable heating element includes an adjustable length heating element and a heating element fixing device. The adjustable length heating element is a single adjustable length heating element rod with external threads at both ends. The heating element fixing device is a ring-shaped cylinder with a heating element fixing thread one and a heating element fixing thread two at both ends on the inner side of the heating element fixing device. The threads of the heating element fixing thread one and the heating element fixing thread two have different directions and a gap exists between them. The heating element fixing thread one engages with the external thread of one adjustable length heating element, and the heating element fixing thread two engages with the external thread of another adjustable length heating element. The outer layer of the heating element fixing device is a heating element fixing sleeve shell.

[0040] The heating element conductive support fixing device is a cuboid in shape. The heating element conductive support fixing device is designed with a heating element conductive support fixing hole 1 that penetrates two parallel planes of length and width. The heating element conductive support fixing hole 1 has an internal thread on the inner side. The conductive support fixing shaft 1 protrudes from the two parallel planes of width and height.

[0041] The internal thread of the heating element conductive support fixing device 1 engages with the external thread of the adjustable heating element, and the two conductive support fixing shafts 1 of the heating element conductive support fixing device 1 are coupled with the gap between the adjustable conductive support 1 and the conductive support fixing device.

[0042] Optionally, the adjustable heating element assembly structure is an adjustable triangular connection heating element assembly structure, which is a cuboid and includes multiple adjustable conductive support groups one, multiple adjustable conductive support groups two, multiple adjustable conductive support groups three, multiple adjustable heating elements, multiple heating element conductive support fixing devices one and multiple heating element conductive support fixing devices two.

[0043] The adjustable conductive support group 2 includes two adjustable conductive supports 2, two adjustable conductive supports 3, four conductive support fixing bolts, two conductive support fixing seats and four conductive support fixing rings. The two adjustable conductive supports 2 are parallel, the two adjustable conductive supports 3 are parallel, the two adjustable conductive supports 2 are above the two adjustable conductive supports 3, and there is a gap between the two adjustable conductive supports 2 and the two adjustable conductive supports 3.

[0044] The adjustable conductive support second includes a conductive support second body and a conductive support second threaded hole. The adjustable conductive support second is a long rectangular parallelepiped with a right angle. At both ends of the right angle, there are protruding plate-shaped rectangular parallelepipeds. The plate-shaped rectangular parallelepipeds are designed with conductive support second threaded holes. The conductive support second threaded holes are designed with internal threads. On one plane of the length and width, the inside of the right angle is tooth-shaped.

[0045] The adjustable conductive support includes a conductive support body and conductive support threaded holes. The conductive support body is a long rectangular prism with a right angle. At both ends of the right angle, there are protruding plate-shaped rectangular prisms. The plate-shaped rectangular prisms are designed with conductive support threaded holes. The conductive support threaded holes are designed with internal threads. On one plane of the length and width, the outer side of the right angle is tooth-shaped.

[0046] The adjustable conductive support group three includes two adjustable conductive supports four, two conductive support fixing devices, four conductive support fixing bolts, two conductive support fixing seats, and four conductive support fixing rings; the two adjustable conductive supports four are parallel, the two conductive support fixing devices are parallel, the two adjustable conductive supports four are above the two conductive support fixing devices, and there is a gap between the two adjustable conductive supports four and the two conductive support fixing devices.

[0047] The adjustable conductive support four is a long rectangular prism. At both ends of the adjustable conductive support four, there are protruding plate-shaped rectangular prisms. The plate-shaped rectangular prisms are designed with threaded holes for the adjustable conductive support four. The threaded holes for the adjustable conductive support four are designed with internal threads. One plane of the length and width of the adjustable conductive support four is serrated.

[0048] The second heating element conductive bracket fixing device is a cuboid. The second heating element conductive bracket fixing device is designed with two parallel planes penetrating the length and width of the heating element conductive bracket fixing hole two. The inner side of the second heating element conductive bracket fixing hole two is designed with internal thread, and the second conductive bracket fixing shaft two protrudes on two adjacent planes of width and height.

[0049] The internal thread of the heating element conductive support fixing device 2 engages with the external thread of the adjustable heating element, and the two conductive support fixing shafts 2 of the heating element conductive support fixing device 2 are coupled with the gap between the adjustable conductive support 2 and the adjustable conductive support 3.

[0050] The two conductive bracket fixing shafts of the heating element conductive bracket fixing device 1 are coupled with the gap between the adjustable conductive bracket 4 and the conductive bracket fixing device 1.

[0051] The conductive support fixing bolt engages with the internal thread of the threaded hole of the adjustable conductive support two, and the conductive support fixing bolt engages with the internal thread of the threaded hole of the conductive support three.

[0052] The beneficial effects of adopting the above technical solution are as follows:

[0053] This invention provides a non-uniform layout optimization method for an adjustable heating element assembly structure. The method uses a neural network to optimize the heating element layout parameters under a specified objective function, including but not limited to furnace temperature uniformity, workpiece temperature uniformity, maximum energy efficiency ratio in the furnace, and workpiece surface heat flux density. The method can obtain the optimal heating element assembly layout parameters that satisfy the physical boundary conditions of the vacuum furnace and the objective function, including but not limited to optimizing the heating element layout parameters of the vacuum sintering furnace.

[0054] The purpose of this invention is to provide a heating element assembly structure with adjustable layout. This adjustable heating element assembly solves the problem that the positions of heating elements are often fixed at the factory and cannot be adjusted. After obtaining the optimal heating element layout parameters that satisfy the objective function and boundary conditions through the neural network-based non-uniform layout parameter optimization method, the adjustable heating element assembly can achieve dynamic adjustment of the heating element length, the heating element spatial layout, and the heating element assembly position. By adjusting the layout of the heating element assembly to the optimal heating element layout parameters, it can optimize furnace temperature uniformity, workpiece temperature uniformity, and the ratio of workpiece surface heat flux density to the maximum energy efficiency ratio in the furnace. Attached Figure Description

[0055] Figure 1 This is a flowchart illustrating a non-uniform layout optimization method for an adjustable heating element assembly structure according to an embodiment of the present invention.

[0056] Figure 2 This is a schematic diagram showing the optimization of the furnace temperature uniformity in a vacuum sintering furnace according to an embodiment of the present invention, compared to the original scheme.

[0057] Figure 3 This is a schematic diagram showing the optimization of workpiece temperature uniformity in a vacuum sintering furnace with a non-uniform layout compared to the original scheme in an embodiment of the present invention.

[0058] Figure 4 This is a schematic diagram of the adjustable parallel heating element group of the vacuum sintering furnace in an embodiment of the present invention, wherein the adjustable conductive support group 101, the adjustable heating element 102, and the heating element conductive support fixing device 103 are included.

[0059] Figure 5 This is a schematic diagram of the adjustable conductive support assembly 101 in an embodiment of the present invention, which includes an adjustable conductive support 1011, a conductive support fixing device 1012, a conductive support fixing bolt 1013, a conductive support fixing seat 1014, and a conductive support fixing ring 1015.

[0060] Figure 6This is a schematic diagram of the adjustable conductive support 1011 in an embodiment of the present invention, which includes an electrode connector 10111, a conductive support body 10112, and a conductive support threaded hole 10113.

[0061] Figure 7 This is a schematic diagram of the structure of the conductive support fixing base 1014 in an embodiment of the present invention;

[0062] Figure 8 This is a partial enlarged view of the conductive support fixing of the adjustable heating body group of the vacuum sintering furnace in an embodiment of the present invention, which includes a conductive support fixing bolt 1013, a conductive support fixing seat 1014, and a conductive support fixing ring 1015.

[0063] Figure 9 This is a schematic diagram of the adjustable heating element 102 in an embodiment of the present invention, which includes an adjustable length heating element 1021, a heating element fixing device 1022, and a heating element conductive support fixing device 103.

[0064] Figure 10 This is a schematic diagram of the adjustable length heating element 1021 in an embodiment of the present invention;

[0065] Figure 11 This is a schematic diagram of the structure of the heating element fixing device 1022 in an embodiment of the present invention, which includes a heating element fixing thread one 10221, a heating element fixing thread two 10222, and a heating element fixing sleeve outer shell 10223;

[0066] Figure 12 This is a schematic diagram of the structure of the heating element conductive support fixing device 103 in an embodiment of the present invention, which includes a heating element conductive support fixing hole 1031 and a conductive support fixing shaft 1032.

[0067] Figure 13 This is a schematic diagram of the adjustable triangular connection heating element assembly in an embodiment of the present invention, which includes an adjustable conductive support assembly 101, an adjustable conductive support assembly 2 104, an adjustable conductive support assembly 3 105, an adjustable heating element 102, a heating element conductive support fixing device 103, and a heating element conductive support fixing device 2 106.

[0068] Figure 14 This is a schematic diagram of the adjustable conductive support assembly 2 104 in an embodiment of the present invention, which includes an adjustable conductive support 2 1041, an adjustable conductive support 3 1042, a conductive support fixing bolt 1013, a conductive support fixing seat 1014, and a conductive support fixing ring 1015.

[0069] Figure 15This is a schematic diagram of the adjustable conductive support 1041 in an embodiment of the present invention, which includes a conductive support body 10411 and a conductive support threaded hole 10412.

[0070] Figure 16 This is a schematic diagram of the adjustable conductive support 1042 in an embodiment of the present invention, which includes a conductive support body 10421 and a conductive support threaded hole 10422.

[0071] Figure 17 This is a schematic diagram of the structure of the second heating element conductive bracket fixing device 106 in an embodiment of the present invention, which includes a second heating element conductive bracket fixing hole 1061 and a second conductive bracket fixing shaft 1062. Detailed Implementation

[0072] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0073] To address the problems existing in the prior art, this invention provides a non-uniform layout optimization method for adjustable heating element assembly structures, combined with... Figure 1 This may include the following steps:

[0074] Step 1: Simulate the heating process of the workpiece in the vacuum sintering furnace based on four sets of heating elements to obtain temperature data. The temperature data includes the average temperature inside the vacuum furnace, the average temperature of multiple cross sections of the heating chamber in the vacuum furnace, the average temperature of the entire workpiece, the temperature of each temperature measurement point on the workpiece, and the initial temperature of the workpiece.

[0075] In the actual implementation process, Ansys can be used to perform Fluent simulation on the optimized non-uniform layout parameters.

[0076] Step 2: Calculate the furnace temperature uniformity σ, sintered workpiece temperature anomaly ε, maximum furnace energy efficiency ratio η, and workpiece surface heat flux density Q / A based on temperature data; use the furnace temperature uniformity σ, sintered workpiece temperature anomaly ε, maximum furnace energy efficiency ratio η, and workpiece surface heat flux density Q / A as output samples, and use the layout parameters X = {x1, x2, x3, x4} of the four heating elements as input samples. The output samples and input samples constitute training samples, and multiple training samples constitute a training sample set.

[0077] Among them, the furnace temperature uniformity σ, the sintered workpiece temperature anomaly ε, the furnace maximum energy efficiency ratio η, and the workpiece surface heat flux density Q / A are calculated based on temperature data using the following formulas:

[0078]

[0079] in, T represents the average temperature inside the vacuum furnace. i is the average temperature of the i-th cross-section of the heating chamber in the vacuum furnace, and n is the number of cross-sections;

[0080]

[0081] in, The temperature represents the average temperature of the entire workpiece, where N represents the number of temperature measurement points taken on the workpiece, and T represents the average temperature of the entire workpiece. j This represents the temperature at the j-th temperature measurement point on the workpiece;

[0082]

[0083] Among them, c g This indicates the specific heat capacity of the workpiece. T represents the average temperature of the entire workpiece, T0 represents the initial temperature of the workpiece, and ρ represents the average temperature of the entire workpiece. g V represents the density of the workpiece. g The volume of the workpiece is represented by P, and the furnace heating power is represented by t. s Indicates heating time;

[0084] Q / A = P1 / A;

[0085] Where P1 is the heat power absorbed or dissipated by the workpiece, and A is the area of ​​the workpiece surface.

[0086] Step 3: Train the CNN neural network model based on the training sample set to obtain a performance parameter optimization model;

[0087] The CNN neural network includes an input layer, hidden layers, and an output layer. The hidden layers are mainly sub-hidden layers with different numbers of neurons connected in sequence. The input function uses the ReLU function as the activation function, while the other layers use the swish function or other commonly used nonlinear functions σ as the activation function.

[0088] Among them, the performance parameter optimization model can accurately express the temperature uniformity σ in the furnace, the temperature variation of the sintered workpiece ε, the maximum energy efficiency ratio in the furnace η, and the heat flux density Q / A on the workpiece surface within the parameter range.

[0089] During the training of the CNN neural network model, the parameters of the CNN neural network model are updated using the energy equation and the DO radiation model equation for discrete coordinates. The energy equation is as follows:

[0090]

[0091] Where ρ is the density of the radiating material. Here, is the Hamiltonian operator, E is the specific total energy (i.e., the total energy per unit mass), t is time, U is velocity (U = 0 in the solid domain), and q is the heat flux. The work done by viscous stress is represented by p, where p is the pressure and S is the work term. e For other lost heat, g is the acceleration due to gravity;

[0092] The equations for the DO radiation model in discrete coordinates are:

[0093]

[0094] Where σ is the Stefan-Boltzman constant; σ s is the scattering coefficient; a is the absorption coefficient; n is the refractive index; r is the Cartesian coordinate of the radiation source in space (x, y, z); s is the unit vector of the radiation direction of the radiation source (n x n y n z ); I is the radiation intensity, dΩ′ is a spherical infinitesimal element; s' is a unit vector in another radiation direction. Let T be the incident radiation intensity and T be the temperature.

[0095] Step 4: Based on the preset range of values ​​for the layout parameters of the four sets of heating elements, an initial population containing 10,000 layout parameters is randomly generated using real number encoding. A chaotic genetic algorithm is used, with a chaotic factor added, and the chaotic migration ratio and iteration number set to screen the initial population to obtain the target population.

[0096] Step 5: Based on the performance parameter optimization model, determine one or more target parameters in the target population, obtain the layout parameters corresponding to the target parameters, and adjust the layout of the four sets of heating elements in the adjustable heating element group structure based on the layout parameters of the four sets of heating elements.

[0097] Among them, based on the performance parameter optimization model, one or more target parameters are determined in the target population, including:

[0098] For each layout parameter in the target population, the layout parameter is input into the performance parameter optimization model to obtain its corresponding temperature parameters. The temperature parameters include furnace temperature uniformity σ, sintered workpiece temperature anomaly ε, furnace maximum energy efficiency ratio η, and workpiece surface heat flux density Q / A, thereby obtaining the target parameters corresponding to all layout parameters. Among all temperature parameters, one or more target parameters are selected. The temperature uniformity σ among the target parameters is the minimum value of all temperature uniformity σ, the sintered workpiece temperature anomaly ε is the maximum value of all sintered workpiece temperature anomaly ε, the furnace maximum energy efficiency ratio η is the maximum value of all furnace maximum energy efficiency ratio η, and the workpiece surface heat flux density Q / A is the maximum value of all workpiece surface heat flux density Q / A.

[0099] Based on the target parameters, the furnace temperature uniformity σ, the sintered workpiece temperature anomaly ε, the maximum energy efficiency ratio η in the furnace, and the workpiece surface heat flux density Q / A, and Figure 2 and Figure 3 The non-uniform layout scheme, namely the scheme of the present invention, can be obtained. Compared with the original layout scheme, the temperature uniformity σ in the furnace is increased by 16%, and the workpiece temperature variability coefficient ε is reduced by 45.12%.

[0100] The adjustable heating element assembly structure consists of four heating element assemblies. Each heating element assembly includes four sub-heating element assemblies. Each sub-heating element assembly includes multiple adjustable conductive supports and multiple adjustable heating elements. One adjustable support is connected to the first end of the adjustable heating element, and another adjustable support is connected to the second end of the adjustable heating element. The multiple adjustable heating elements are parallel to each other.

[0101] Combine Figure 4 The adjustable heating element group structure is an adjustable parallel heating element group structure, which consists of four heating element groups. Each heating element group includes four sub-heating element groups. Each sub-heating element group includes two adjustable conductive support groups 101, multiple adjustable heating elements 102, and multiple heating element conductive support fixing devices 103.

[0102] Combine Figure 5 The adjustable conductive support assembly 101 includes two adjustable conductive supports 1011, two conductive support fixing devices 1012, four conductive support fixing bolts 1013, two conductive support fixing seats 1014, and four conductive support fixing rings 1015; the two adjustable conductive supports 1011 are parallel, the two conductive support fixing devices 1012 are parallel, the two adjustable conductive supports 1011 are above the two conductive support fixing devices 1012, and there is a gap between the two adjustable conductive supports 1011 and the two conductive support fixing devices 1012;

[0103] Combine Figure 6The adjustable conductive support 1011 includes an electrode connector 10111 and a conductive support body 10112. The conductive support body 10112 is a long rectangular parallelepiped. Protruding plate-shaped rectangular parallelepipeds are designed at both ends of the adjustable conductive support 10111. The plate-shaped rectangular parallelepipeds are designed with conductive support threaded holes 10113, which are designed with internal threads. One plane of the length and width of the conductive support body 10112 is serrated. The length and height planes of the conductive support body 10112 are connected to the electrode connector 10111. The electrode connector 10111 is a plate-shaped rectangular parallelepiped. The electrode connector 10111 is designed with holes penetrating the centers of two parallel length and width planes. The length and height planes of the electrode connector 10111 are connected to the length and height planes of the conductive support body 10112.

[0104] Among them, the electrode connector 10111 and the vacuum furnace electrode lead are connected by a flexible connection to achieve circuit flow.

[0105] The conductive support fixing device 1012 is a long rectangular parallelepiped. The two planar ends of the conductive support fixing device 1012, which are wide and high, are designed with protruding plate-shaped rectangular parallelepipeds. The plate-shaped rectangular parallelepipeds are designed with conductive support fixing device threaded holes 10121. The conductive support fixing device threaded holes 10121 are designed with internal threads. One plane of the length and width of the conductive support fixing device 1012 is serrated.

[0106] Combine Figure 7 The conductive support fixing seat 1014 is a long rectangular parallelepiped, and the conductive support fixing seat is designed with a long hole that runs through two planes, the length and the width.

[0107] Combine Figure 8 The conductive support fixing bolt 1013 is designed with external threads, and the conductive support fixing ring 1015 is designed with internal threads. The external threads of the conductive support fixing bolt 1013 and the internal threads of the conductive support fixing ring 1015 engage.

[0108] The conductive bracket fixing bolt 1013 engages with the internal thread of the conductive bracket threaded hole 10113, the conductive bracket fixing bolt 1013 engages with the hole of the conductive bracket fixing seat 1014, and the conductive bracket fixing bolt 1013 engages with the internal thread of the conductive bracket fixing device threaded hole 10121.

[0109] Combine Figure 9 The adjustable heating element 102 includes an adjustable-length heating element 1021 and a heating element fixing device 1022. The adjustable-length heating element 1021 is an adjustable-length heating element single rod, combined with... Figure 10 The adjustable-length heating element has external threads at both ends, and the heating element fixing device 1022 is a ring-shaped cylinder. Figure 11 The inner ends of the heating element fixing device 1022 are designed with heating element fixing thread one 10221 and heating element fixing thread two 10222. The thread directions of heating element fixing thread one 10221 and heating element fixing thread two 10222 are different, and there is a gap between heating element fixing thread one 10221 and heating element fixing thread two 10222. Heating element fixing thread one 10221 engages with the external thread of an adjustable length heating element, and heating element fixing thread two 10222 engages with the external thread of another adjustable length heating element. The outer layer of the heating element fixing device 1022 is a heating element fixing sleeve outer shell 10223.

[0110] The adjustable heating element 102 should have some expansion space to prevent the material from expanding at high temperatures. The adjustable heating element is made of graphite and has threads at both ends. The length of the heating element is 20cm.

[0111] Combine Figure 12 The heating element conductive support fixing device 103 is a cuboid in shape. The heating element conductive support fixing device is designed with heating element conductive support fixing holes 1031 that penetrate two parallel planes of length and width. The heating element conductive support fixing holes 1031 are designed with internal threads on the inside. The conductive support fixing shaft 1032 protrudes from the two parallel planes of width and height.

[0112] Among them, the heating element conductive support fixing device 103 is made of graphite, and its outer surface is coated with a 0.5mm tantalum carbide coating to increase stability, and its inner surface is threaded.

[0113] The internal thread of the heating element conductive support fixing device 103 engages with the external thread of the adjustable heating element 102. The two conductive support fixing shafts 1032 of the heating element conductive support fixing device 103 are coupled with the gap between the adjustable conductive support 1011 and the conductive support fixing device 1012.

[0114] Combine Figure 13 The adjustable heating element assembly structure is an adjustable triangular connection heating element assembly structure, which is a cuboid and includes multiple adjustable conductive support groups 101, multiple adjustable conductive support groups 2 104, multiple adjustable conductive support groups 3 105, multiple adjustable heating elements 102, multiple heating element conductive support fixing devices 1 103 and multiple heating element conductive support fixing devices 2 106.

[0115] Combine Figure 14The adjustable conductive support group 2 104 includes two adjustable conductive supports 2 1041, two adjustable conductive supports 3 1042, four conductive support fixing bolts 1013, two conductive support fixing seats 1014, and four conductive support fixing rings 1015. The two adjustable conductive supports 2 1041 are parallel, the two adjustable conductive supports 3 1042 are parallel, the two adjustable conductive supports 2 1041 are above the two adjustable conductive supports 3 1042, and there is a gap between the two adjustable conductive supports 2 1041 and the two adjustable conductive supports 3 1042.

[0116] Combine Figure 15 The adjustable conductive support 1041 includes a conductive support body 10411 and a conductive support threaded hole 10412. The conductive support body 10411 is a long rectangular parallelepiped with a right angle. At both ends of the right angle, there are protruding plate-shaped rectangular parallelepipeds. The plate-shaped rectangular parallelepipeds are designed with conductive support threaded holes 10412. The conductive support threaded holes 10412 are designed with internal threads. On one plane of the length and width, the inside of the right angle is tooth-shaped.

[0117] Combine Figure 16 The adjustable conductive support 1042 includes a conductive support body 10421 and a conductive support threaded hole 10422. The conductive support body 10421 is a long rectangular parallelepiped with a right angle. At both ends of the right angle, there are protruding plate-shaped rectangular parallelepipeds. The plate-shaped rectangular parallelepipeds are designed with conductive support threaded holes 10422. The conductive support threaded holes 10422 are designed with internal threads. On one plane of length and width, on the outside of the right angle, there are teeth.

[0118] The adjustable conductive support assembly 105 includes two adjustable conductive supports 1051, two conductive support fixing devices 1012, four conductive support fixing bolts 1013, two conductive support fixing seats 1014, and four conductive support fixing rings 1015; the two adjustable conductive supports 1051 are parallel, the two conductive support fixing devices 1012 are parallel, the two adjustable conductive supports 1051 are above the two conductive support fixing devices 1012, and there is a gap between the two adjustable conductive supports 1051 and the two conductive support fixing devices 1012;

[0119] The adjustable conductive support 1051 is a long rectangular parallelepiped. At both ends of the adjustable conductive support 1051, there are protruding plate-shaped rectangular parallelepipeds. The plate-shaped rectangular parallelepipeds are designed with threaded holes 10511 for the conductive support 10511. The threaded holes 10511 for the conductive support 10511 are designed with internal threads. One plane of the length and width of the adjustable conductive support 1051 is serrated.

[0120] Combine Figure 17The second heating element conductive bracket fixing device 106 is a cuboid. The second heating element conductive bracket fixing device 106 is designed with two parallel planes that penetrate the length and width of the heating element conductive bracket fixing hole 1061. The inner side of the second heating element conductive bracket fixing hole 1061 is designed with internal thread. The second conductive bracket fixing shaft 1062 protrudes from two adjacent planes of width and height.

[0121] The internal thread of the heating element conductive support fixing device 2 106 engages with the external thread of the adjustable heating element 102, and the two conductive support fixing shafts 2 1062 of the heating element conductive support fixing device 2 106 are coupled with the gap between the adjustable conductive support 2 1041 and the adjustable conductive support 3 1042.

[0122] The two conductive support fixing shafts 1032 of the heating element conductive support fixing device 103 are coupled with the gap between the adjustable conductive support 1051 and the conductive support fixing device 1012.

[0123] The conductive bracket fixing bolt 1013 engages with the internal thread of the threaded hole of the adjustable conductive bracket 2 1041, and the conductive bracket fixing bolt 1013 engages with the internal thread of the threaded hole 10422 of the conductive bracket 3.

[0124] The adjustable heating element assembly solves the problem that the current heating element assembly is fixed and cannot be adjusted according to the actual situation, and also solves the problem that the heating element is not easy to disassemble or replace.

[0125] The above description is merely a preferred embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of this disclosure.

Claims

1. A method for optimizing the non-uniform layout of a layout-adjustable heating element assembly, characterized in that, include: Step 1: Simulate the heating process of the workpiece in the vacuum sintering furnace based on four sets of heating elements to obtain temperature data. The temperature data includes the average temperature inside the vacuum furnace, the average temperature of multiple cross sections of the heating chamber in the vacuum furnace, the average temperature of the entire workpiece, the temperature of each temperature measurement point on the workpiece, and the initial temperature of the workpiece. Step 2: Calculate the furnace temperature uniformity σ, sintered workpiece temperature anomaly ε, maximum furnace energy efficiency ratio η, and workpiece surface heat flux density Q / A based on temperature data; use the furnace temperature uniformity σ, sintered workpiece temperature anomaly ε, maximum furnace energy efficiency ratio η, and workpiece surface heat flux density Q / A as output samples, and use the layout parameters of the four sets of heating elements as input samples. The output samples and input samples constitute training samples, and multiple training samples constitute a training sample set. Step 3: Train the CNN neural network model based on the training sample set to obtain a performance parameter optimization model; During the training of the CNN neural network model, the parameters of the CNN neural network model are updated using the energy equation and the DO radiation model equation for discrete coordinates. The energy equation is as follows: Where ρ is the density of the radiating material. Here, is the Hamiltonian operator, E is the specific total energy (i.e., the total energy per unit mass), t is time, U is velocity (U = 0 in the solid domain), and q is the heat flux. The work done by viscous stress is represented by p, where p is the pressure and S is the work term. e For other lost heat, g is the acceleration due to gravity; The equations for the DO radiation model in discrete coordinates are: Where σ is the Stefan-Boltzman constant; σ s is the scattering coefficient; a is the absorption coefficient; n is the refractive index; r is the Cartesian coordinate of the radiation source in space (x, y, z); s is the unit vector of the radiation direction of the radiation source (n x n y n z ); I is the radiation intensity, dΩ′ is the spherical infinitesimal element; s' is the unit vector in another radiation direction, φ is the incident radiation intensity, and T is the temperature; Step 4: Based on the preset range of values ​​for the layout parameters of the four sets of heating elements, an initial population containing 10,000 layout parameters is randomly generated using real number encoding. A chaotic genetic algorithm is used, with a chaotic factor added, and the chaotic migration ratio and iteration number set to screen the initial population to obtain the target population. Step 5: Based on the performance parameter optimization model, determine one or more target parameters in the target population, obtain the layout parameters corresponding to the target parameters, and adjust the layout of the four sets of heating elements in the adjustable heating element group structure based on the layout parameters of the four sets of heating elements.

2. The method for optimizing the non-uniform layout of an adjustable heating element assembly structure according to claim 1, characterized in that, In step 2, the furnace temperature uniformity σ, the sintered workpiece temperature anomaly ε, the furnace maximum energy efficiency ratio η, and the workpiece surface heat flux density Q / A are calculated based on the temperature data using the following formulas: in, T represents the average temperature inside the vacuum furnace. i is the average temperature of the i-th cross-section of the heating chamber in the vacuum furnace, and n is the number of cross-sections; in, The temperature represents the average temperature of the entire workpiece, where N represents the number of temperature measurement points taken on the workpiece, and T represents the average temperature of the entire workpiece. j This represents the temperature at the j-th temperature measurement point on the workpiece; Among them, c g This indicates the specific heat capacity of the workpiece. T represents the average temperature of the entire workpiece, T0 represents the initial temperature of the workpiece, and ρ represents the average temperature of the entire workpiece. g V represents the density of the workpiece. g The volume of the workpiece is represented by P, and the furnace heating power is represented by t. s Indicates heating time; Q / A = P1 / A; Where P1 is the heat power absorbed or dissipated by the workpiece, and A is the area of ​​the workpiece surface.

3. The non-uniform layout optimization method for an adjustable heating element assembly structure according to claim 1, characterized in that, In step 5, based on the performance parameter optimization model, one or more target parameters are determined in the target population, including: For each layout parameter in the target population, the layout parameter is input into the performance parameter optimization model to obtain its corresponding temperature parameters. The temperature parameters include furnace temperature uniformity σ, sintered workpiece temperature anomaly ε, furnace maximum energy efficiency ratio η, and workpiece surface heat flux density Q / A, thereby obtaining the target parameters corresponding to all layout parameters. Among all temperature parameters, one or more target parameters are selected. The temperature uniformity σ among the target parameters is the minimum value of all temperature uniformity σ, the sintered workpiece temperature anomaly ε is the maximum value of all sintered workpiece temperature anomaly ε, the furnace maximum energy efficiency ratio η is the maximum value of all furnace maximum energy efficiency ratio η, and the workpiece surface heat flux density Q / A is the maximum value of all workpiece surface heat flux density Q / A.

4. The method for optimizing the non-uniform layout of an adjustable heating element assembly structure according to claim 1, characterized in that, The adjustable heating element assembly structure consists of four heating element assemblies. Each heating element assembly includes four sub-heating element assemblies. Each sub-heating element assembly includes multiple adjustable conductive supports and multiple adjustable heating elements. One adjustable support is connected to the first end of the adjustable heating element, and another adjustable support is connected to the second end of the adjustable heating element. The multiple adjustable heating elements are parallel to each other.

5. The non-uniform layout optimization method for an adjustable heating element assembly structure according to claim 4, characterized in that, The adjustable heating element group structure is an adjustable parallel heating element group structure, which consists of four heating element groups. Each heating element group includes four sub-heating element groups. Each sub-heating element group includes two adjustable conductive support groups, multiple adjustable heating elements, and multiple heating element conductive support fixing devices. The adjustable conductive support assembly includes two adjustable conductive supports, two conductive support fixing devices, four conductive support fixing bolts, two conductive support fixing seats, and four conductive support fixing rings; the two adjustable conductive supports are parallel, the two conductive support fixing devices are parallel, the two adjustable conductive supports are above the two conductive support fixing devices, and there is a gap between the two adjustable conductive supports and the two conductive support fixing devices. The adjustable conductive support includes an electrode connector and a conductive support body. The conductive support body is a long rectangular parallelepiped with protruding plate-shaped rectangular parallelepipeds at both ends. Each plate-shaped rectangular parallelepiped has a threaded hole with internal threads. One plane of the length and width of the conductive support body is serrated, and the planes of the length and height of the conductive support body are connected to the electrode connector. The electrode connector is a plate-shaped rectangular parallelepiped with holes penetrating the centers of two parallel planes of length and width. The planes of the length and height of the electrode connector are connected to the planes of the length and height of the conductive support body. The conductive support fixing device is a long rectangular prism. The two planar ends of the width and height of the conductive support fixing device are designed with protruding plate-shaped rectangular prisms. The plate-shaped rectangular prisms are designed with threaded holes for the conductive support fixing device. The threaded holes for the conductive support fixing device are designed with internal threads. One plane of the length and width of the conductive support fixing device is serrated. The conductive support holder is a long rectangular prism, and the conductive support holder is designed with a long hole that runs through two planes, the length and the width. The conductive support fixing bolt is designed with external threads, and the conductive support fixing ring is designed with internal threads. The external threads of the conductive support fixing bolt and the internal threads of the conductive support fixing ring mesh. The conductive bracket fixing bolt engages with the internal thread of a threaded hole in the conductive bracket, the conductive bracket fixing bolt engages with the hole in the conductive bracket fixing seat, and the conductive bracket fixing bolt engages with the internal thread of the threaded hole in the conductive bracket fixing device. The adjustable heating element includes an adjustable length heating element and a heating element fixing device. The adjustable length heating element is a single adjustable length heating element rod with external threads at both ends. The heating element fixing device is a ring-shaped cylinder with a heating element fixing thread one and a heating element fixing thread two at both ends on the inner side of the heating element fixing device. The threads of the heating element fixing thread one and the heating element fixing thread two have different directions and a gap exists between them. The heating element fixing thread one engages with the external thread of one adjustable length heating element, and the heating element fixing thread two engages with the external thread of another adjustable length heating element. The outer layer of the heating element fixing device is a heating element fixing sleeve shell. The heating element conductive support fixing device is a cuboid in shape. The heating element conductive support fixing device is designed with a heating element conductive support fixing hole 1 that penetrates two parallel planes of length and width. The heating element conductive support fixing hole 1 has an internal thread on the inner side. The conductive support fixing shaft 1 protrudes from the two parallel planes of width and height. The internal thread of the heating element conductive support fixing device 1 engages with the external thread of the adjustable heating element, and the two conductive support fixing shafts 1 of the heating element conductive support fixing device 1 are coupled with the gap between the adjustable conductive support 1 and the conductive support fixing device.

6. The method for optimizing the non-uniform layout of an adjustable heating element assembly structure according to claim 5, characterized in that, The adjustable heating element assembly structure is an adjustable triangular connection heating element assembly structure, which is a cuboid and includes multiple adjustable conductive support groups one, multiple adjustable conductive support groups two, multiple adjustable conductive support groups three, multiple adjustable heating elements, multiple heating element conductive support fixing device one, and multiple heating element conductive support fixing device two. The adjustable conductive support group 2 includes two adjustable conductive supports 2, two adjustable conductive supports 3, four conductive support fixing bolts, two conductive support fixing seats and four conductive support fixing rings. The two adjustable conductive supports 2 are parallel, the two adjustable conductive supports 3 are parallel, the two adjustable conductive supports 2 are above the two adjustable conductive supports 3, and there is a gap between the two adjustable conductive supports 2 and the two adjustable conductive supports 3. The adjustable conductive support second includes a conductive support second body and a conductive support second threaded hole. The adjustable conductive support second is a long rectangular parallelepiped with a right angle. At both ends of the right angle, there are protruding plate-shaped rectangular parallelepipeds. The plate-shaped rectangular parallelepipeds are designed with conductive support second threaded holes. The conductive support second threaded holes are designed with internal threads. On one plane of the length and width, the inside of the right angle is tooth-shaped. The adjustable conductive support includes a conductive support body and conductive support threaded holes. The conductive support body is a long rectangular prism with a right angle. At both ends of the right angle, there are protruding plate-shaped rectangular prisms. The plate-shaped rectangular prisms are designed with conductive support threaded holes. The conductive support threaded holes are designed with internal threads. On one plane of the length and width, the outer side of the right angle is tooth-shaped. The adjustable conductive support group three includes two adjustable conductive supports four, two conductive support fixing devices, four conductive support fixing bolts, two conductive support fixing seats, and four conductive support fixing rings; the two adjustable conductive supports four are parallel, the two conductive support fixing devices are parallel, the two adjustable conductive supports four are above the two conductive support fixing devices, and there is a gap between the two adjustable conductive supports four and the two conductive support fixing devices. The adjustable conductive support four is a long rectangular prism. At both ends of the adjustable conductive support four, there are protruding plate-shaped rectangular prisms. The plate-shaped rectangular prisms are designed with threaded holes for the adjustable conductive support four. The threaded holes for the adjustable conductive support four are designed with internal threads. One plane of the length and width of the adjustable conductive support four is serrated. The second heating element conductive bracket fixing device is a cuboid. The second heating element conductive bracket fixing device is designed with two parallel planes penetrating the length and width of the heating element conductive bracket fixing hole two. The inner side of the second heating element conductive bracket fixing hole two is designed with internal thread, and the second conductive bracket fixing shaft two protrudes on two adjacent planes of width and height. The internal thread of the heating element conductive support fixing device 2 engages with the external thread of the adjustable heating element, and the two conductive support fixing shafts 2 of the heating element conductive support fixing device 2 are coupled with the gap between the adjustable conductive support 2 and the adjustable conductive support 3. The two conductive bracket fixing shafts of the heating element conductive bracket fixing device 1 are coupled with the gap between the adjustable conductive bracket 4 and the conductive bracket fixing device 1. The conductive support fixing bolt engages with the internal thread of the threaded hole of the adjustable conductive support two, and the conductive support fixing bolt engages with the internal thread of the threaded hole of the conductive support three.

Images