CN111737779A - Simulation method for barium titanate ceramic PTC thermal management structure of vehicle-mounted air conditioner - Google Patents
Simulation method for barium titanate ceramic PTC thermal management structure of vehicle-mounted air conditioner Download PDFInfo
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- 239000000919 ceramic Substances 0.000 title claims abstract description 153
- 229910002113 barium titanate Inorganic materials 0.000 title claims abstract description 102
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 title claims abstract description 73
- 238000000034 method Methods 0.000 title claims abstract description 58
- 238000004088 simulation Methods 0.000 title claims abstract description 20
- 239000007787 solid Substances 0.000 claims abstract description 58
- 238000012546 transfer Methods 0.000 claims abstract description 44
- 238000004806 packaging method and process Methods 0.000 claims abstract description 16
- 229910052782 aluminium Inorganic materials 0.000 claims description 60
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 60
- 239000012530 fluid Substances 0.000 claims description 53
- 239000010410 layer Substances 0.000 claims description 43
- 239000000110 cooling liquid Substances 0.000 claims description 32
- 239000000758 substrate Substances 0.000 claims description 27
- 238000010168 coupling process Methods 0.000 claims description 26
- 239000000463 material Substances 0.000 claims description 23
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 19
- 238000007789 sealing Methods 0.000 claims description 18
- 239000012790 adhesive layer Substances 0.000 claims description 17
- 238000010438 heat treatment Methods 0.000 claims description 15
- 238000010408 sweeping Methods 0.000 claims description 15
- 238000001816 cooling Methods 0.000 claims description 13
- 229910052574 oxide ceramic Inorganic materials 0.000 claims description 13
- 239000011224 oxide ceramic Substances 0.000 claims description 13
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 13
- 230000008878 coupling Effects 0.000 claims description 12
- 238000005859 coupling reaction Methods 0.000 claims description 12
- 238000010586 diagram Methods 0.000 claims description 11
- 239000000853 adhesive Substances 0.000 claims description 10
- 230000001070 adhesive effect Effects 0.000 claims description 10
- 239000000654 additive Substances 0.000 claims description 8
- 230000000996 additive effect Effects 0.000 claims description 8
- 238000004364 calculation method Methods 0.000 claims description 8
- 239000000084 colloidal system Substances 0.000 claims description 6
- 230000004907 flux Effects 0.000 claims description 6
- 238000012545 processing Methods 0.000 claims description 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 5
- 238000004378 air conditioning Methods 0.000 claims description 5
- 239000000741 silica gel Substances 0.000 claims description 5
- 229910002027 silica gel Inorganic materials 0.000 claims description 5
- 230000009471 action Effects 0.000 claims description 4
- 238000013213 extrapolation Methods 0.000 claims description 4
- 238000011144 upstream manufacturing Methods 0.000 claims description 4
- 239000003086 colorant Substances 0.000 claims description 3
- 238000009434 installation Methods 0.000 claims description 3
- 230000017525 heat dissipation Effects 0.000 abstract description 11
- 238000011160 research Methods 0.000 abstract description 6
- 230000007246 mechanism Effects 0.000 abstract description 2
- 239000003292 glue Substances 0.000 description 7
- 230000008569 process Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 4
- 238000012805 post-processing Methods 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 239000002826 coolant Substances 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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- 238000011161 development Methods 0.000 description 1
- 238000002224 dissection Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
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- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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Abstract
The invention discloses a method for simulating a barium titanate ceramic PTC thermal management structure of a vehicle-mounted air conditioner. The invention belongs to the technical field of barium titanate ceramic PTC thermal management structure simulation, and a barium titanate ceramic PTC thermal management structure model is established; adding a physical field to the barium titanate ceramic PTC thermal management structure model, and combining a current field, a solid heat transfer field and an electromagnetic thermal field; establishing a temperature interpolation function according to a current field based on a barium titanate ceramic PTC thermal management structure model, and setting a PTC ceramic conductivity parameter; a grid splitting method is adopted to split the PTC thermal management structure model to obtain grid distribution and a grid quality report; and solving the PTC heat management structure model to complete the simulation of the vehicle-mounted air conditioner barium titanate ceramic PTC heat management structure. The invention researches factors and parameters influencing the heat dissipation capacity of the PTC packaging structure, analyzes the mechanism of various factors influencing the heat dissipation of the structure, and provides measures for improving the heat dissipation capacity of the PTC packaging structure.
Description
Technical Field
The invention relates to the technical field of simulation of barium titanate ceramic PTC (positive temperature coefficient) thermal management structures, in particular to a method for simulating a barium titanate ceramic PTC thermal management structure of a vehicle-mounted air conditioner.
Background
The PTC heating element gradually replaces the traditional metal heating element due to the constant temperature heating capability and safety, and has wide application prospect in the field of automobile air conditioners. However, at present, the PTC heating elements are mostly bonded by using an organic silicon adhesive, and the extremely low thermal conductivity of the organic silicon adhesive reduces the heat dissipation capability of the PTC packaging structure and reduces the heating power of the elements, so that the service life is adversely affected, and therefore, the heat management research on the PTC heating element packaging structure is strongly necessary.
Disclosure of Invention
The invention provides a method for simulating a barium titanate ceramic PTC heat management structure of a vehicle-mounted air conditioner, and provides the following technical scheme for researching factors and parameters influencing the heat dissipation capacity of a PTC packaging structure, analyzing the mechanism of various factors influencing the heat dissipation of the structure and providing measures for improving the heat dissipation capacity of the PTC packaging structure:
a method for simulating a barium titanate ceramic PTC thermal management structure of a vehicle-mounted air conditioner comprises the following steps:
step 1: establishing a barium titanate ceramic PTC thermal management structure model according to the sizes of the barium titanate PTC, the aluminum electrode plate and the aluminum oxide ceramic substrate;
step 2: adding a physical field to the barium titanate ceramic PTC thermal management structure model, and combining a current field, a solid heat transfer field and an electromagnetic thermal field;
and step 3: establishing a temperature interpolation function according to a current field based on a barium titanate ceramic PTC thermal management structure model, and setting a PTC ceramic conductivity parameter;
and 4, step 4: a grid splitting method is adopted to split the barium titanate ceramic PTC thermal management structure model to obtain grid distribution and a grid quality report;
and 5: and solving the barium titanate ceramic PTC thermal management structure model to complete the simulation of the vehicle-mounted air conditioner barium titanate ceramic PTC thermal management structure.
Preferably, the step 1 specifically comprises the steps of determining the sizes of the barium titanate ceramic PTC, the aluminum electrode plate and the aluminum oxide ceramic substrate, setting the sizes of the barium titanate ceramic PTC, the aluminum electrode plate and the aluminum oxide ceramic substrate as global definition parameters, creating a three-dimensional assembly based on COMSOL Multiphysics to establish a barium titanate ceramic PTC thermal management structure model, wherein the model adopts BaTiO 9 × 13A ceramic distribution array.
Preferably, the creating of the three-dimensional component based on comsolmutiphysics to establish the barium titanate ceramic PTC thermal management structure model specifically comprises:
creating a cuboid as an aluminum oxide ceramic substrate, drawing a sketch of the aluminum electrode plate by taking one side surface as a working surface, and stretching to create the aluminum electrode plate; creating 9 small cuboids side by side on an aluminum electrode as BaTiO3A ceramic; in BaTiO3Drawing a sketch on the outer surface of the ceramic and stretching to create another aluminum electrode plate;
obtaining 2 aluminum electrode plates and 9 BaTiO plates by Boolean operation3A ceramic union, wherein a difference set of a cuboid and the union is used as outer ring sealing rubber;
and (3) creating a flat cuboid to represent another alumina ceramic substrate, and inputting position parameters according to the actual positions of the components in the element to complete the creation of the barium titanate ceramic PTC thermal management structure model.
Preferably, the barium titanate ceramic PTC thermal management structure model is treated as a thin layer structure, material interfaces of all layers are defined as adhesive layers, an explicit layer is set as a thermal thickness thin layer in a solid heat transfer physical field, the thickness of the thin layer is set as a global definition parameter d _ additive, a fixed value is 100mm when the array form and the colloid thermal conductivity are packaged, and the parameter d _ additive is changed in the global definition when the thickness of the adhesive layer is formed;
removing the protruding part of the aluminum electrode pin during modeling, and ensuring that the end surface of the outer side of the pin is flush with the outer surface of the sealing silica gel; and processing the base cross beam of the aluminum installation groove and the element contact wall into a thin layer structure, wherein the thickness of the thin layer and the wall thickness are set to be 1 mm.
Preferably, the step 2 specifically comprises:
when a current solid heat transfer coupling method is adopted, in a current field, 450V voltage is applied to one aluminum electrode pin, and the other aluminum electrode pin is grounded; in the solid heat transfer field, the initial temperature is set to be 20 ℃, and the ambient temperature is set to be 20 ℃; simulating cooling conditions by using heat flux boundary conditions, wherein the cooling conditions comprise forced convection heat exchange of cooling liquid and natural convection heat exchange of other surfaces and air; establishing a thermal thick thin layer on the boundary combined adhesive layer for simulating an adhesive layer, wherein the material is adhesive, the thickness is d _ adhesive, the electromagnetic thermal field adopts a thermoelectric coupling field and is used for calculating joule heat according to current density to serve as a heat source for solid heat transfer, so that a current field is connected with the solid heat transfer field, and a coupling interface selects the set current field and the set solid heat transfer field;
when a current solid and fluid heat transfer laminar flow coupling method is adopted, 450V voltage is applied to one electrode pin, and the other electrode pin is grounded; in the solid and fluid heat transfer field, the model is set as a solid, and the outer cooling liquid model is set as a fluid; the initial temperature of the element and the ambient temperature are still set to 20 ℃; air natural convection heat exchange is respectively arranged on the upper surface, the lower surface and the two side surfaces of the heating element, and the medium, the temperature and the characteristic length are kept unchanged; defining an inflow boundary condition on one side of the cooling liquid model, wherein the upstream temperature is 20 ℃, and the other side of the cooling liquid model is defined as an outflow boundary condition; in the laminar flow field, two side cooling liquid models are selected from fluid attributes as the action domain of the laminar flow field, and the initial speed in each direction in the initial value is 0; defining inlet fluid boundary conditions on two boundaries acted by inflow thermal boundary conditions, wherein the inflow speed is 2m/s, and defining outlet fluid boundary conditions on two boundaries acted by outflow thermal boundary conditions, the pressure is 0Pa, and backflow is inhibited; and the boundary condition of the fluid wall is kept to be set in a default mode, namely the outer surface of the cooling liquid model except the fluid inlet and the fluid outlet are taken as the fluid wall, the electromagnetic thermal field coupling interface selects the current field, the solid thermal field and the fluid thermal field, and the current field, the solid thermal field and the electromagnetic thermal field are combined.
Preferably, the step 3 specifically comprises: according to the measured electricity at each temperatureMethod for establishing BaTiO by combining discrete data with ceramic wafer size and utilizing COMSOL self-contained interpolation and piecewise function3Ceramic conductivity parameter function in BaTiO3Establishing two interpolation functions of resistance with respect to temperature under the ceramic parameter node, wherein one temperature interval is from 0 ℃ to 185 ℃, the other temperature interval is from 185 ℃ to 250 ℃, and inputting BaTiO at different temperatures3The resistance value of the ceramic chip is interpolated in a linear unit mode, and the extrapolation mode is a nearest function;
establishing a section function as a function of the conductivity with respect to the temperature, wherein the section point is a Curie temperature point, the section point is a conductivity function expressed by a low-temperature resistance function below the Curie temperature, the section point is a conductivity function expressed by a high-temperature resistance function above the Curie temperature, and the section point is in the BaTiO3The conductivity function is added to the column for the conductivity parameter of the ceramic.
Preferably, the step 4 specifically includes:
step 4.1: a barium titanate ceramic PTC thermal management structure model is subdivided by adopting a free tetrahedral mesh in a BaTiO3Drawing a free quadrilateral grid on the surface of one side of the ceramic, ensuring to obtain a regular rectangular grid consistent with the shape by adjusting the distribution on each side, completely subdividing 9 PTC ceramics by using a cuboid grid by sweeping, and changing the number of units in the Z-axis direction into 5 units by using a distribution command in order to conveniently simulate the internal temperature distribution of the BaTiO3 ceramic;
step 4.2: the electrode pins of the two aluminum sheets are subjected to free quadrilateral mesh subdivision, rectangular meshes of the aluminum electrode sheets are built through sweeping, and the rectangular meshes are divided into 2 units on a Z axis;
step 4.3: subdividing the contact surface of the sealing rubber and the alumina by using a free triangular mesh, establishing a mesh of an outermost alumina ceramic substrate by sweeping, and dividing the alumina ceramic substrate into 2 units in the Z-axis direction of the sweeping mesh; and (4) dividing the rest sealing rubber by using a free tetrahedral mesh to complete mesh division of the whole assembly, and obtaining a mesh distribution and a mesh quality report.
Preferably, the step 5 specifically comprises:
solving a barium titanate ceramic PTC thermal management structure model in COMSOLMUTIPhysics, after a result is obtained by the solving, establishing a drawing group under a result node of a model developer to draw a temperature field calculation result into a temperature distribution diagram, establishing two three-dimensional drawing groups under the result node, respectively naming the drawing groups as PTC ceramic temperature distribution and outer surface temperature distribution, adding a sheet graph in the PTC ceramic temperature distribution three-dimensional drawing to represent the PTC ceramic temperature distribution, selecting all PTC ceramics as a drawing range, wherein the unit is degC, and a color table is of a Rainbow type; adding a volume maximum value graph and a volume minimum value graph to mark the temperature extreme value on the PTC ceramic, selecting all the PTC ceramic as a drawing range, selecting a unit degC, wherein the precision is 4-digit effective numbers, and marking background color and selecting white;
adding a surface map to the three-dimensional drawing group of the external surface temperature distribution to show the external surface temperature distribution, selecting all external surfaces as drawing ranges and units of degC, and selecting a color table in a ThermalLight reverse order type; and adding the maximum value and the minimum value of the surface to mark the temperature extreme value on the outer surface, selecting all the outer surfaces as drawing ranges, selecting the unit degC, and marking background colors to select white, thereby completing the simulation of the vehicle-mounted air-conditioning barium titanate ceramic PTC thermal management structure.
The invention has the following beneficial effects:
the invention introduces a process for establishing a model of a PTC packaging structure in COMSOLULTIPhysics software, which comprises four steps of geometric model establishment, material addition, physical field addition and mesh generation. When a geometric model is established, in order to simplify the model and facilitate calculation, the PTC packaging structure is processed and adjusted, including electrode pin simplification and glue layer thickness thinning; when adding materials, BaTiO3The conductivity of the ceramic changes with the temperature and only has actually measured discrete data points, so that a piecewise function with respect to the temperature needs to be established by taking the Curie temperature as a piecewise point to define BaTiO3Electrical conductivity of the ceramic; when the physical field is added, the setting of cooling conditions, namely the convection heat transfer conditions of the outer surface, needs to be paid attention to; when the mesh is divided, the quality of the manual mesh division is obviously superior to that of the free tetrahedral mesh, so that the manual mesh division is uniformly used in the whole research process.
After the model is built, the PCT packaging structure is heatedManaging simulation calculation, and researching BaTiO through structure temperature distribution under different parameters3The influence of the ceramic distribution array, the glue layer thickness, the colloid thermal conductivity and the cooling condition on the heat dissipation capacity of the PTC packaging structure. The simulation results show that BaTiO3The ceramic 3 × 3 distribution array 9 × 1 array can improve the heat dissipation capability of the structure, the higher the colloid heat conductivity, the smaller the glue layer thickness and the faster the cooling liquid flow rate, the stronger the heat dissipation capability of the packaging structure, and the temperature of the cooling liquid has no obvious influence on the heat dissipation of the packaging structure.
Drawings
FIG. 1 is a diagram of component geometric models in a model developer set;
FIG. 2 is a schematic view of a package structure model, FIG. 2- (a) is an appearance effect diagram, and FIG. 2- (b) is a wire frame effect diagram;
FIG. 3 is a diagram of physical field settings;
FIG. 4 is a diagram of layer flow field boundary condition settings;
FIG. 5 shows BaTiO in the model developer3Three function graphs established under the material parameter nodes;
FIG. 6 shows BaTiO3A plot of a function of a ceramic parameter;
FIG. 7 is a free tetrahedron subdivision grid quality report diagram;
FIG. 8 is a manually generated grid quality report graph;
FIG. 9 is a temperature profile setup diagram in a model developer;
FIG. 10 is a flow chart of a method for simulating a barium titanate ceramic PTC thermal management structure of a vehicle-mounted air conditioner.
Detailed Description
The present invention will be described in detail with reference to specific examples.
The first embodiment is as follows:
according to fig. 10, the application provides a method for simulating a barium titanate ceramic PTC thermal management structure of a vehicle-mounted air conditioner, which comprises the following steps:
step 1: establishing a barium titanate ceramic PTC thermal management structure model according to the sizes of the barium titanate PTC, the aluminum electrode plate and the aluminum oxide ceramic substrate;
determining the sizes of the barium titanate ceramic PTC, the aluminum electrode plate and the aluminum oxide ceramic substrate, setting the sizes of the barium titanate ceramic PTC, the aluminum electrode plate and the aluminum oxide ceramic substrate as global definition parameters, creating a three-dimensional assembly based on COMSOLMIC to establish a barium titanate ceramic PTC thermal management structure model, wherein the model adopts 9 × 1BaTiO of3A ceramic distribution array.
The method for establishing the barium titanate ceramic PTC heat management structure model by establishing the three-dimensional assembly based on COMSOLULTIPhysics specifically comprises the following steps:
creating a cuboid as an aluminum oxide ceramic substrate, drawing a sketch of the aluminum electrode plate by taking one side surface as a working surface, and stretching to create the aluminum electrode plate; creating 9 small cuboids side by side on an aluminum electrode as BaTiO3A ceramic; in BaTiO3Drawing a sketch on the outer surface of the ceramic and stretching to create another aluminum electrode plate;
obtaining 2 aluminum electrode plates and 9 BaTiO plates by Boolean operation3A ceramic union, wherein a difference set of a cuboid and the union is used as outer ring sealing rubber;
and (3) creating a flat cuboid to represent another alumina ceramic substrate, and inputting position parameters according to the actual positions of the components in the element to complete the creation of the barium titanate ceramic PTC thermal management structure model.
Treating a barium titanate ceramic PTC thermal management structure model as a thin layer structure, defining material interfaces of all layers as adhesive layers, setting an explicit layer as a thermal thickness thin layer in a solid heat transfer physical field, setting the thickness of the thin layer as a global definition parameter d _ additive, taking a fixed value of 100mm when packaging an array form and colloid thermal conductivity, and changing the parameter d _ additive in the global definition when the thickness of an adhesive layer is thick;
removing the protruding part of the aluminum electrode pin during modeling, and ensuring that the end surface of the outer side of the pin is flush with the outer surface of the sealing silica gel; and processing the base cross beam of the aluminum installation groove and the element contact wall into a thin layer structure, wherein the thickness of the thin layer and the wall thickness are set to be 1 mm.
Step 2: adding a physical field to the barium titanate ceramic PTC thermal management structure model, and combining a current field, a solid heat transfer field and an electromagnetic thermal field;
the step 2 specifically comprises the following steps:
when a current solid heat transfer coupling method is adopted, in a current field, 450V voltage is applied to one aluminum electrode pin, and the other aluminum electrode pin is grounded; in the solid heat transfer field, the initial temperature is set to be 20 ℃, and the ambient temperature is set to be 20 ℃; simulating cooling conditions by using heat flux boundary conditions, wherein the cooling conditions comprise forced convection heat exchange of cooling liquid and natural convection heat exchange of other surfaces and air; establishing a thermal thick thin layer on the boundary combined adhesive layer for simulating an adhesive layer, wherein the material is adhesive, the thickness is d _ adhesive, the electromagnetic thermal field adopts a thermoelectric coupling field and is used for calculating joule heat according to current density to serve as a heat source for solid heat transfer, so that a current field is connected with the solid heat transfer field, and a coupling interface selects the set current field and the set solid heat transfer field;
when a current solid and fluid heat transfer laminar flow coupling method is adopted, 450V voltage is applied to one electrode pin, and the other electrode pin is grounded; in the solid and fluid heat transfer field, the model is set as a solid, and the outer cooling liquid model is set as a fluid; the initial temperature of the element and the ambient temperature are still set to 20 ℃; air natural convection heat exchange is respectively arranged on the upper surface, the lower surface and the two side surfaces of the heating element, and the medium, the temperature and the characteristic length are kept unchanged; defining an inflow boundary condition on one side of the cooling liquid model, wherein the upstream temperature is 20 ℃, and the other side of the cooling liquid model is defined as an outflow boundary condition; in the laminar flow field, two side cooling liquid models are selected from fluid attributes as the action domain of the laminar flow field, and the initial speed in each direction in the initial value is 0; defining inlet fluid boundary conditions on two boundaries acted by inflow thermal boundary conditions, wherein the inflow speed is 2m/s, and defining outlet fluid boundary conditions on two boundaries acted by outflow thermal boundary conditions, the pressure is 0Pa, and backflow is inhibited; and the boundary condition of the fluid wall is kept to be set in a default mode, namely the outer surface of the cooling liquid model except the fluid inlet and the fluid outlet are taken as the fluid wall, the electromagnetic thermal field coupling interface selects the current field, the solid thermal field and the fluid thermal field, and the current field, the solid thermal field and the electromagnetic thermal field are combined.
And step 3: establishing a temperature interpolation function according to a current field based on a barium titanate ceramic PTC thermal management structure model, and setting a PTC ceramic conductivity parameter;
the step 3 specifically comprises the following steps: establishing BaTiO by utilizing COMSOL self-contained interpolation and piecewise function according to the measured resistance discrete data at each temperature and the size of the ceramic chip3Ceramic conductivity parameter function in BaTiO3Establishing two interpolation functions of resistance with respect to temperature under the ceramic parameter node, wherein one temperature interval is from 0 ℃ to 185 ℃, the other temperature interval is from 185 ℃ to 250 ℃, and inputting BaTiO at different temperatures3The resistance value of the ceramic chip is interpolated in a linear unit mode, and the extrapolation mode is a nearest function;
establishing a section function as a function of the conductivity with respect to the temperature, wherein the section point is a Curie temperature point, the section point is a conductivity function expressed by a low-temperature resistance function below the Curie temperature, the section point is a conductivity function expressed by a high-temperature resistance function above the Curie temperature, and the section point is in the BaTiO3The conductivity function is added to the column for the conductivity parameter of the ceramic.
And 4, step 4: a grid splitting method is adopted to split the barium titanate ceramic PTC thermal management structure model to obtain grid distribution and a grid quality report;
the step 4 specifically comprises the following steps:
step 4.1: a barium titanate ceramic PTC thermal management structure model is subdivided by adopting a free tetrahedral mesh in a BaTiO3Drawing a free quadrilateral grid on the surface of one side of the ceramic, ensuring to obtain a regular rectangular grid consistent with the shape by adjusting the distribution on each side, completely subdividing 9 PTC ceramics by using a cuboid grid by sweeping, and changing the number of units in the Z-axis direction into 5 units by using a distribution command in order to conveniently simulate the internal temperature distribution of the BaTiO3 ceramic;
step 4.2: the electrode pins of the two aluminum sheets are subjected to free quadrilateral mesh subdivision, rectangular meshes of the aluminum electrode sheets are built through sweeping, and the rectangular meshes are divided into 2 units on a Z axis;
step 4.3: subdividing the contact surface of the sealing rubber and the alumina by using a free triangular mesh, establishing a mesh of an outermost alumina ceramic substrate by sweeping, and dividing the alumina ceramic substrate into 2 units in the Z-axis direction of the sweeping mesh; and (4) dividing the rest sealing rubber by using a free tetrahedral mesh to complete mesh division of the whole assembly, and obtaining a mesh distribution and a mesh quality report.
And 5: and solving the barium titanate ceramic PTC thermal management structure model to complete the simulation of the vehicle-mounted air conditioner barium titanate ceramic PTC thermal management structure.
The step 5 specifically comprises the following steps:
solving a barium titanate ceramic PTC thermal management structure model in COMSOLMUTIPhysics, after a result is obtained by the solving, establishing a drawing group under a result node of a model developer to draw a temperature field calculation result into a temperature distribution diagram, establishing two three-dimensional drawing groups under the result node, respectively naming the drawing groups as PTC ceramic temperature distribution and outer surface temperature distribution, adding a sheet graph in the PTC ceramic temperature distribution three-dimensional drawing to represent the PTC ceramic temperature distribution, selecting all PTC ceramics as a drawing range, wherein the unit is degC, and a color table is of a Rainbow type; adding a volume maximum value graph and a volume minimum value graph to mark the temperature extreme value on the PTC ceramic, selecting all the PTC ceramic as a drawing range, selecting a unit degC, wherein the precision is 4-digit effective numbers, and marking background color and selecting white;
adding a surface map to the three-dimensional drawing group of the external surface temperature distribution to show the external surface temperature distribution, selecting all external surfaces as drawing ranges and units of degC, and selecting a color table in a ThermalLight reverse order type; and adding the maximum value and the minimum value of the surface to mark the temperature extreme value on the outer surface, selecting all the outer surfaces as drawing ranges, selecting the unit degC, and marking background colors to select white, thereby completing the simulation of the vehicle-mounted air-conditioning barium titanate ceramic PTC thermal management structure.
The second embodiment is as follows:
in the COMSOLLMultiphilics software, the establishment process of a complete model comprises four steps of geometric model establishment, material addition, physical field application and mesh generation. In order to obtain an accurate simulation result, the structure and the size of the component are ensured to be correct, the material parameters are accurate, the physical field is complete, and the mesh subdivision is reasonable.
Step 1: the dimensions of the barium titanate PTC ceramic, aluminum electrode sheet, alumina ceramic substrate used have been listed in the previous section, with the dimensional parameters first set to globally defined parameters to facilitate later recall of table 1 when building the geometric model using comsolmutics software.
Table 1 global definition parameters to be used
After necessary dimension parameters are input into the global definition, a three-dimensional assembly can be initially created in COMSOLULTIPhysics as a geometric model of the PTC heating element, wherein the geometric model building process is 9 × 1BaTiO 13A ceramic distribution array is presented as an example.
Firstly, creating a cuboid as an aluminum oxide ceramic substrate, drawing a sketch of an aluminum electrode plate by taking one side surface as a working surface, and stretching to create the aluminum electrode plate; creating 9 small cuboids side by side on an aluminum electrode as BaTiO3A ceramic; in BaTiO3Drawing a sketch on the outer surface of the ceramic and stretching to create another aluminum electrode plate; obtaining 2 aluminum electrode plates and 9 BaTiO plates by using Boolean operation3A ceramic union set, wherein after a cuboid is created, the difference between the cuboid and the union set is used as outer ring sealing rubber; creating another flat cuboid representing another piece of alumina ceramic substrate; the physical dimensions of the components are listed in table 2, and the position parameters need to be input according to the actual positions of the components in the element, and fig. 1 shows the composition of the geometric model and the position parameters of the components in the model developer.
TABLE 2 component physical dimensions
It should be noted that the model is processed three times during the process of establishing the model so as to facilitate the mesh generation and the calculation solution. One is the glue layer between each layer of material, because the thickness of the glue layer is too small, the mesh dissection is complex, so a glue layer solid model is not established, and the glue layer solid model is treated as a thin layer structure. Defining a material interface of each layer as an explicit type called an adhesive layer in the assembly, setting the explicit type as a thermal thickness thin layer in a solid heat transfer physical field, setting the thickness of the thin layer as a global definition parameter d _ additive, taking a fixed value of 100mm when researching a packaging array form and colloid thermal conductivity, and changing the parameter d _ additive in the global definition when researching the thickness of an adhesive layer; and secondly, due to the existence of the aluminum electrode pins, the appearance of the whole heating element is irregular, and the sealing rubber grids at the pins and adjacent to the pins are fine and complex, so that the protruding parts of the pins are removed during modeling, and the outer end surfaces of the pins are ensured to be flush with the outer surface of the sealing silica gel. And thirdly, processing the aluminum mounting groove base beam and the element contact wall into a thin layer structure, wherein the operation method is the same as that of the adhesive layer, and the thickness and the wall thickness of the thin layer are set to be 1 mm. The resulting geometric model is shown in fig. 2.
And 2, adding a physical field, wherein in COMSOLULTIPhysics software, two addition schemes are adopted for the physical field in which the PTC heating element works, namely a current-solid heat transfer coupling method and a current-solid and fluid heat transfer-laminar flow coupling method according to the scheme shown in figure 3.
Current-solid heat transfer coupling method
The method involves three physical fields, namely a current field, a solid heat transfer field and an electromagnetic thermal field. In the current field, 450V voltage is applied to one aluminum electrode pin, and the other aluminum electrode pin is grounded. In the solid heat transfer field, the initial temperature is set to be 20 ℃, and the ambient temperature is set to be 20 ℃; the cooling conditions were simulated using heat flux boundary conditions, including forced convective heat transfer of the coolant and natural convective heat transfer of other surfaces with air. In addition, a thin thermal thickness layer needs to be built on the boundary combination adhesive layer selected previously to simulate an adhesive layer, the material is adhesive, and the thickness is d _ adhesive. The electromagnetic thermal field is a thermal coupling field and is used for calculating joule heat as a heat source for solid heat transfer according to current density so as to connect the current field with the solid heat transfer field, and the coupling interface is used for selecting the set current field and the set solid heat transfer field.
Current-solid and fluid heat transfer-laminar flow coupling method
This method involves four physical fields, respectively current field, solid and fluid heat transfer field, laminar flow field and electromagnetic thermal field, requiring the creation of additional geometric models of coolant outside the alumina ceramic substrate, see fig. 4.
The current field is the same as in the previous method, with 450V applied to one electrode pin and the other electrode pin grounded.
In the solid and fluid heat transfer field, firstly, a geometric model of the heating element is set as a solid, and a geometric model of the cooling liquid at the outer side is set as a fluid; the initial temperature of the element and the ambient temperature are still set to 20 ℃; air natural convection heat exchange is respectively arranged on the upper surface, the lower surface and the two side surfaces of the heating element, and the medium, the temperature and the characteristic length are kept unchanged; the inflow boundary conditions are defined on one side of the geometric model of the cooling fluid, the upstream temperature is 20 ℃, and the outflow boundary conditions are defined on the other side.
In the laminar flow field, a geometric model of the cooling liquid on two sides is selected from fluid attributes and is used as a laminar flow field action domain, and the initial speed in each direction in the initial value is 0; defining inlet fluid boundary conditions on two boundaries acted by inflow thermal boundary conditions, wherein the inflow speed is 2m/s, and defining outlet fluid boundary conditions on two boundaries acted by outflow thermal boundary conditions, the pressure is 0Pa, and backflow is inhibited; the fluid wall boundary condition is kept at the default setting, namely the outer surface of the cooling liquid geometric model is regarded as the fluid wall except the fluid inlet and the fluid outlet.
The electromagnetic thermal field coupling interface is selected from a current field and a solid and fluid heat transfer field, and the function is the same as that of the first scheme.
Physical field comparison and selection:
through comparison, the two physical field schemes mainly have different cooling liquid cooling condition simulation methods, the current-solid heat transfer coupling method adds a forced heat exchange boundary condition on the surface of a solid geometric model, and the cooling liquid cooling effect is defined by medium materials, temperature and flow rate; and additionally establishing a cooling liquid fluid model by a current-solid and fluid heat transfer-laminar flow coupling method, and defining the cooling effect of the cooling liquid through the fluid material, the flow speed of the laminar flow field and the temperature.
The current-solid heat transfer coupling method does not need to establish a cooling liquid fluid model and introduce a laminar flow field, so that the calculation of a solver is simpler; the geometric model and physical field of the current-solid and fluid heat transfer-laminar flow coupling method are relatively complex, but the temperature distribution of the cooling liquid can be obtained.
the material parameters needed by simulation in COMSOLLMultiphilics are determined by the type of physical field on the geometric model, most of the material parameters can be found in COMSOL built-in material library or obtained by inquiring related data, and only various materials need to be added and the domain applied by the materials needs to be selected in the modeling process.
However, the current field requires the conductivity parameter of the material, while BaTiO3The functional relation of the ceramic conductivity changing along with the temperature needs to be built and added, so that the BaTiO is built by utilizing COMSOL self-contained interpolation and piecewise function according to the measured resistance discrete data under various temperatures and the size of the ceramic chip3Ceramic conductivity parameter function. Firstly, in BaTiO3Establishing two interpolation functions of resistance with respect to temperature under the ceramic parameter node, wherein one temperature interval is from 0 ℃ to 185 ℃, the other temperature interval is from 185 ℃ to 250 ℃, and inputting BaTiO at different temperatures3And the resistance value of the ceramic chip is interpolated in a linear unit mode, and the extrapolation mode is a nearest function. Another piecewise function is then established as a function of conductivity versus temperature, the piecewise point being the curie temperature point (185 ℃), below the curie temperature being a conductivity function expressed by a low temperature resistance function, and above the curie temperature being a conductivity function expressed by a high temperature resistance function. Finally in BaTiO3And filling the ceramic conductivity parameter column with a set conductivity piecewise function. FIGS. 5 and 6 are diagrams for setting BaTiO, respectively3Three functions established for the conductivity of ceramics and their images.
Two mesh generation methods, free tetrahedral mesh and manual mesh generation, were tried. First, the whole geometric model is subdivided by using a free tetrahedral mesh, and the method is very simple and quick, and a net quality report is obtained as shown in fig. 7.
According to the grid distribution and grid quality report, the grid quality is not high by directly dividing the whole geometric model by using the free tetrahedron, and the rectangular grid is determined to be divided as much as possible by using a manual dividing method instead in consideration of the fact that the shapes of all parts of the PTC packaging structure are more regular and the number of the rectangular bodies is large, so that the grid quality is improved.
Firstly, BaTiO3Drawing a free quadrilateral mesh on the surface of one side of the ceramic, ensuring to obtain a regular rectangular mesh similar to the appearance by adjusting the distribution on each side, then completely subdividing 9 PTC ceramics by using the cuboid mesh by sweeping, and conveniently simulating BaTiO3Changing the number of units in the Z-axis direction into 5 units by using a distribution command; and secondly, performing free quadrilateral mesh subdivision on electrode pins of the two aluminum sheets, establishing a cuboid mesh of the aluminum electrode sheet by sweeping, and dividing the cuboid mesh into 2 units on a Z axis. The reason is that on one hand, the heat conducting capacity of the aluminum is strong and the aluminum sheet is very thin, so that the temperature change of the aluminum sheet in the Z-axis direction cannot be too large, and on the other hand, the temperature distribution of the aluminum sheet is not the key point of research, so that the quality reduction and unnecessary solving complexity caused by the over-fine mesh are avoided only by rough subdivision; and thirdly, subdividing the contact surface of the sealing rubber and the alumina by using a free triangular mesh, and establishing the mesh of the outermost alumina ceramic substrate by sweeping, wherein the Z-axis distribution of the swept mesh of the alumina ceramic substrate is also divided into 2 units based on the same reason. Finally, the remaining sealing rubber is subdivided by using free tetrahedral meshes to complete mesh subdivision of the whole assembly, and a mesh quality report is obtained as shown in fig. 8.
It can be seen that most of the manually-split meshes are regular cuboids and have similar sizes, the quality of most of the meshes is high, the quality of the free tetrahedral meshes of the sealing rubber near the aluminum electrode pins is poor, the overall average cell quality reaches 0.7634 and is obviously higher than that of the first splitting method of all the free tetrahedral meshes, and therefore if no special description is provided, the meshes are uniformly split according to the second method.
After the results are obtained by solving the COMSOLMUTIPhysics software, a drawing group needs to be established under the result nodes of the model developer to draw the temperature field calculation results into a temperature distribution graph, and the section mainly introduces a post-processing method for visualizing the simulation results.
According to the actual needs of the research content, two three-dimensional drawing sets are established under the result node, namely a PTC ceramic temperature distribution and an outer surface temperature distribution. Adding a sheet graph in the PTC ceramic temperature distribution three-dimensional drawing to represent the PTC ceramic temperature distribution, selecting all PTC ceramics as drawing ranges, wherein the unit is degC, and the color table is of a Rainbow type; and adding a volume maximum value/minimum value graph for marking the temperature extreme value on the PTC ceramic, selecting all the PTC ceramic as a drawing range, wherein the unit degC is 4-digit effective number, and marking background color and selecting white.
Adding a surface map to the three-dimensional drawing group of the external surface temperature distribution to show the external surface temperature distribution, selecting all external surfaces as drawing ranges and units of degC, and selecting a color table in a ThermalLight reverse order type; and adding the maximum value/minimum value of the surface to mark the temperature extreme value on the outer surface, selecting all the outer surfaces as drawing ranges, selecting units of degC, and selecting white with the precision of 4-digit effective numbers, and marking the background color. The relevant temperature profile settings under the resulting nodes in the model development tree are shown in FIG. 9.
The invention discloses a method for simplifying a model in a model building process, which comprises the following steps: shortening electrode pins, processing a silica gel layer thermal thick thin layer, and processing an aluminum wall thermal thick thin layer.
Simulation method of cooling conditions during physical field application: the method comprises the following steps that (1) convection heat exchange of cooling liquid is simulated by defining heat flux boundary conditions on the outer surface of an alumina substrate, the type is forced convection heat exchange, the characteristic dimension is the element dimension in the flow velocity direction of the cooling liquid, and the type, the flow velocity and the external temperature of fluid are input according to actual cooling liquid parameters; the natural convection heat exchange of other surfaces and air is simulated by defining heat flux conditions on each surface, the type is natural convection heat exchange, the characteristic size is determined according to the surface size of the element, the fluid is air, and the temperature is the ambient temperature of the element.
The mesh generation method comprises the following steps: compared with automatic tetrahedral mesh generation, the manual mesh generation method can obviously improve the mesh quality, and is favorable for improving the precision of a simulation result.
And (4) a result post-processing method: the method for drawing the two temperature distribution maps (the outer surface temperature distribution map and the PTC ceramic temperature distribution map) can express the temperature integral distribution and the temperature extreme value in the same map, and is more convenient for analysis and research through the temperature distribution maps.
The above description is only a preferred embodiment of the method for simulating the vehicle-mounted air-conditioning barium titanate ceramic PTC thermal management structure, and the protection range of the method for simulating the vehicle-mounted air-conditioning barium titanate ceramic PTC thermal management structure is not limited to the above embodiments, and all technical solutions belonging to the idea belong to the protection range of the invention. It should be noted that modifications and variations which do not depart from the gist of the invention will be those skilled in the art to which the invention pertains and which are intended to be within the scope of the invention.
Claims (8)
1. A method for simulating a barium titanate ceramic PTC thermal management structure of a vehicle-mounted air conditioner is characterized by comprising the following steps: the method comprises the following steps:
step 1: establishing a barium titanate ceramic PTC thermal management structure model according to the sizes of the barium titanate PTC, the aluminum electrode plate and the aluminum oxide ceramic substrate;
step 2: adding a physical field to the barium titanate ceramic PTC thermal management structure model, and combining a current field, a solid heat transfer field and an electromagnetic thermal field;
and step 3: establishing a temperature interpolation function according to a current field based on a barium titanate ceramic PTC thermal management structure model, and setting a PTC ceramic conductivity parameter;
and 4, step 4: a grid splitting method is adopted to split the barium titanate ceramic PTC thermal management structure model to obtain grid distribution and a grid quality report;
and 5: and solving the barium titanate ceramic PTC thermal management structure model to complete the simulation of the vehicle-mounted air conditioner barium titanate ceramic PTC thermal management structure.
2. The method for simulating the barium titanate ceramic PTC thermal management structure of the vehicle air conditioner according to claim 1, wherein the method comprises the following steps: the step 1 specifically comprises the following steps: determining the sizes of the PTC and aluminum electrode plates of the barium titanate ceramics and the aluminum oxide ceramic substrate, and setting according to the sizes of the PTC and aluminum electrode plates of the barium titanate ceramics and the aluminum oxide ceramic substrateFor global parameter definition, creating a three-dimensional assembly based on COMSOLULTIPhysics to establish a barium titanate ceramic PTC thermal management structure model, wherein the model adopts BaTiO 9 × 13A ceramic distribution array.
3. The method for simulating the barium titanate ceramic PTC thermal management structure of the vehicle air conditioner according to claim 2, wherein the method comprises the following steps: the method for establishing the barium titanate ceramic PTC heat management structure model by establishing the three-dimensional assembly based on COMSOL Multiphysics specifically comprises the following steps:
creating a cuboid as an aluminum oxide ceramic substrate, drawing a sketch of the aluminum electrode plate by taking one side surface as a working surface, and stretching to create the aluminum electrode plate; creating 9 small cuboids side by side on an aluminum electrode as BaTiO3A ceramic; in BaTiO3Drawing a sketch on the outer surface of the ceramic and stretching to create another aluminum electrode plate;
obtaining 2 aluminum electrode plates and 9 BaTiO plates by Boolean operation3A ceramic union, wherein a difference set of a cuboid and the union is used as outer ring sealing rubber;
and (3) creating a flat cuboid to represent another alumina ceramic substrate, and inputting position parameters according to the actual positions of the components in the element to complete the creation of the barium titanate ceramic PTC thermal management structure model.
4. The method for simulating the barium titanate ceramic PTC thermal management structure of the vehicle air conditioner according to claim 2, wherein the method comprises the following steps: treating a barium titanate ceramic PTC thermal management structure model as a thin layer structure, defining material interfaces of all layers as adhesive layers, setting an explicit layer as a thermal thickness thin layer in a solid heat transfer physical field, setting the thickness of the thin layer as a global definition parameter d _ additive, taking a fixed value of 100mm when packaging an array form and colloid thermal conductivity, and changing the parameter d _ additive in the global definition when the thickness of an adhesive layer is thick;
removing the protruding part of the aluminum electrode pin during modeling, and ensuring that the end surface of the outer side of the pin is flush with the outer surface of the sealing silica gel; and processing the base cross beam of the aluminum installation groove and the element contact wall into a thin layer structure, wherein the thickness of the thin layer and the wall thickness are set to be 1 mm.
5. The method for simulating the barium titanate ceramic PTC thermal management structure of the vehicle air conditioner according to claim 1, wherein the method comprises the following steps: the step 2 specifically comprises the following steps:
when a current solid heat transfer coupling method is adopted, in a current field, 450V voltage is applied to one aluminum electrode pin, and the other aluminum electrode pin is grounded; in the solid heat transfer field, the initial temperature is set to be 20 ℃, and the ambient temperature is set to be 20 ℃; simulating cooling conditions by using heat flux boundary conditions, wherein the cooling conditions comprise forced convection heat exchange of cooling liquid and natural convection heat exchange of other surfaces and air; establishing a thermal thick thin layer on the boundary combined adhesive layer for simulating an adhesive layer, wherein the material is adhesive, the thickness is d _ adhesive, the electromagnetic thermal field adopts a thermoelectric coupling field and is used for calculating joule heat according to current density to serve as a heat source for solid heat transfer, so that a current field is connected with the solid heat transfer field, and a coupling interface selects the set current field and the set solid heat transfer field;
when a current solid and fluid heat transfer laminar flow coupling method is adopted, 450V voltage is applied to one electrode pin, and the other electrode pin is grounded; in the solid and fluid heat transfer field, the model is set as a solid, and the outer cooling liquid model is set as a fluid; the initial temperature of the element and the ambient temperature are still set to 20 ℃; air natural convection heat exchange is respectively arranged on the upper surface, the lower surface and the two side surfaces of the heating element, and the medium, the temperature and the characteristic length are kept unchanged; defining an inflow boundary condition on one side of the cooling liquid model, wherein the upstream temperature is 20 ℃, and the other side of the cooling liquid model is defined as an outflow boundary condition; in the laminar flow field, two side cooling liquid models are selected from fluid attributes as the action domain of the laminar flow field, and the initial speed in each direction in the initial value is 0; defining inlet fluid boundary conditions on two boundaries acted by inflow thermal boundary conditions, wherein the inflow speed is 2m/s, and defining outlet fluid boundary conditions on two boundaries acted by outflow thermal boundary conditions, the pressure is 0Pa, and backflow is inhibited; and the boundary condition of the fluid wall is kept to be set in a default mode, namely the outer surface of the cooling liquid model except the fluid inlet and the fluid outlet are taken as the fluid wall, the electromagnetic thermal field coupling interface selects the current field, the solid thermal field and the fluid thermal field, and the current field, the solid thermal field and the electromagnetic thermal field are combined.
6. The method for simulating the barium titanate ceramic PTC thermal management structure of the vehicle air conditioner according to claim 1, wherein the method comprises the following steps: the step 3 specifically comprises the following steps: establishing BaTiO by utilizing COMSOL self-contained interpolation and piecewise function according to the measured resistance discrete data at each temperature and the size of the ceramic chip3Ceramic conductivity parameter function in BaTiO3Establishing two interpolation functions of resistance with respect to temperature under the ceramic parameter node, wherein one temperature interval is from 0 ℃ to 185 ℃, the other temperature interval is from 185 ℃ to 250 ℃, and inputting BaTiO at different temperatures3The resistance value of the ceramic chip is interpolated in a linear unit mode, and the extrapolation mode is a nearest function;
establishing a section function as a function of the conductivity with respect to the temperature, wherein the section point is a Curie temperature point, the section point is a conductivity function expressed by a low-temperature resistance function below the Curie temperature, the section point is a conductivity function expressed by a high-temperature resistance function above the Curie temperature, and the section point is in the BaTiO3The conductivity function is added to the column for the conductivity parameter of the ceramic.
7. The method for simulating the barium titanate ceramic PTC thermal management structure of the vehicle air conditioner according to claim 1, wherein the method comprises the following steps: the step 4 specifically comprises the following steps:
step 4.1: a barium titanate ceramic PTC thermal management structure model is subdivided by adopting a free tetrahedral mesh in a BaTiO3Drawing a free quadrilateral grid on the surface of one side of the ceramic, ensuring to obtain a regular rectangular grid consistent with the shape by adjusting the distribution on each side, completely subdividing 9 PTC ceramics by using a cuboid grid by sweeping, and changing the number of units in the Z-axis direction into 5 units by using a distribution command in order to conveniently simulate the internal temperature distribution of the BaTiO3 ceramic;
step 4.2: the electrode pins of the two aluminum sheets are subjected to free quadrilateral mesh subdivision, rectangular meshes of the aluminum electrode sheets are built through sweeping, and the rectangular meshes are divided into 2 units on a Z axis;
step 4.3: subdividing the contact surface of the sealing rubber and the alumina by using a free triangular mesh, establishing a mesh of an outermost alumina ceramic substrate by sweeping, and dividing the alumina ceramic substrate into 2 units in the Z-axis direction of the sweeping mesh; and (4) dividing the rest sealing rubber by using a free tetrahedral mesh to complete mesh division of the whole assembly, and obtaining a mesh distribution and a mesh quality report.
8. The method for simulating the barium titanate ceramic PTC thermal management structure of the vehicle air conditioner according to claim 1, wherein the method comprises the following steps: the step 5 specifically comprises the following steps:
solving a barium titanate ceramic PTC thermal management structure model in COMSOL Multiphysics, after obtaining a result after solving, establishing a drawing group under a result node of a model developer to draw a temperature field calculation result into a temperature distribution diagram, establishing two three-dimensional drawing groups under the result node, respectively naming the drawing groups as PTC ceramic temperature distribution and outer surface temperature distribution, adding a sheet of drawing in the PTC ceramic temperature distribution three-dimensional drawing to represent the PTC ceramic temperature distribution, selecting all PTC ceramics as a drawing range, wherein the unit is degC, and a color table is of a Rainbow type; adding a volume maximum value graph and a volume minimum value graph to mark the temperature extreme value on the PTC ceramic, selecting all the PTC ceramic as a drawing range, selecting a unit degC, wherein the precision is 4-digit effective numbers, and marking background color and selecting white;
adding a surface map to the three-dimensional drawing group of the external surface temperature distribution to show the external surface temperature distribution, selecting all external surfaces as drawing ranges and units of degC, and selecting a color table in a Thermal Light reverse order type; and adding the maximum value and the minimum value of the surface to mark the temperature extreme value on the outer surface, selecting all the outer surfaces as drawing ranges, selecting the unit degC, and marking background colors to select white, thereby completing the simulation of the vehicle-mounted air-conditioning barium titanate ceramic PTC thermal management structure.
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| CN113985122A (en) * | 2021-11-01 | 2022-01-28 | 苏州亿马半导体科技有限公司 | SiC power analysis method based on SolidWorks Flow Simulation |
| CN114741939A (en) * | 2022-06-14 | 2022-07-12 | 武汉光谷航天三江激光产业技术研究院有限公司 | Metal diaphragm tightening method and equipment based on temperature control stress |
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