CN110941882A - A method for thermal analysis of composite materials with curvilinear interface - Google Patents

A method for thermal analysis of composite materials with curvilinear interface Download PDF

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CN110941882A
CN110941882A CN201910988709.XA CN201910988709A CN110941882A CN 110941882 A CN110941882 A CN 110941882A CN 201910988709 A CN201910988709 A CN 201910988709A CN 110941882 A CN110941882 A CN 110941882A
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interface
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composite material
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CN110941882B (en
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曹富军
袁冬芳
刘忻梅
白梅花
莫娟
石琳
葛素琴
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Inner Mongolia University of Science and Technology
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Abstract

本发明公开了一种具有曲线界面的复合材料的热性能分析方法,本发明为二维问题具有曲线界面类型的多层复合材料的热性能提供一种快速,精确的数值分析方法;本方法通过对物理过程的合理近似,提出了描述界面上物理量跳跃的界面连接条件;并结合二维定常热传导方程对多层复合材料的传热过程进行数学描述;同时,利用浸入界面方法对控制方程和界面条件进行离散,并得到了一个稳定、收敛且具有二阶精度的数值格式;本发明通过对二维复合材料具有曲线界面类型的问题,建立了数学模型及数值模拟的方法,本方法可以用来对夹芯钢材,套筒模件等多层复合材料的热传导过程和热阻性能进行高精度的快速分析方法。

Figure 201910988709

The invention discloses a thermal property analysis method of a composite material with a curved interface. The invention provides a fast and accurate numerical analysis method for the thermal properties of a two-dimensional problem of a multilayer composite material with a curved interface type; the method adopts For a reasonable approximation of the physical process, the interface connection conditions that describe the jump of physical quantities on the interface are proposed; the heat transfer process of the multilayer composite material is mathematically described by combining with the two-dimensional steady heat conduction equation; at the same time, the control equation and the interface are analyzed by the immersion interface method. The conditions are discretized, and a stable, convergent numerical format with second-order precision is obtained; the present invention establishes a mathematical model and a numerical simulation method through the problem that the two-dimensional composite material has a curve interface type, and the method can be used for A high-precision rapid analysis method for the thermal conduction process and thermal resistance performance of sandwich steel, sleeve modules and other multi-layer composite materials.

Figure 201910988709

Description

Thermal performance analysis method of composite material with curved interface
Technical Field
The invention relates to the application field of multi-medium composite materials, in particular to a thermal performance analysis method of a composite material with a curved interface.
Background
With the development of scientific technology and industrial production, people put higher demands on heat conducting materials. Compared with the traditional heat conduction materials (metal, metal oxide, ceramic and the like), the high polymer heat conduction composite material is concerned by the scientific community because of the advantages of low price, small relative density, easy processing, short molding period and the like. Heat-conducting polymer composites have been successfully used in a variety of fields and are increasingly in demand, such as the fields of illumination, aerospace, automotive, electronics, and batteries. The thermal conductivity of composites having thermal interfaces has received much attention from researchers. The thermal interface material is a composite material which is prepared by filling heat-conducting particles with a high polymer material serving as a matrix. The thermal interface material can effectively improve the heat conduction between two solid interfaces and plays an important role in the performance, the service life and the stability of an electronic device. Particularly, when two solid interfaces are in direct contact, the actual contact area between the interfaces is very small due to the roughness of the interfaces, and is only 1% -2% of the apparent contact area, and the interface contact thermal resistance is very large at the moment. Therefore, the thermal conductivity of the thermal interface composite material is rapidly and quantitatively analyzed, and the research significance and the application value of the performance research, development and effective utilization of the thermal interface material are very good.
At present, most of the thermal performance research of the composite material adopts an experimental research method, the experimental method is limited by the complexity of experimental equipment and the composite material and the arbitrary constraint of an interface, and a comprehensive and systematic analysis on the thermal performance of the tested material is difficult to realize. On the other hand, many researchers have proposed theoretical models, such as equivalent thermal conductivity models of two-phase composites, based on experiments and data for some simple two-phase composites. In addition, researchers adopt a Monte Carlo numerical simulation method to perform statistical analysis on the phenomenon that the composite material has a wide distribution of random unequal diameter pore canals by adopting ANSYS software. The invention provides a method based on the combination of a physical property mechanism and mathematical modeling, which carries out comprehensive, accurate and detailed numerical analysis on the heat conduction process of a composite material by solving a control equation of the heat conduction process of the composite material. The method is not limited by the interface geometry of the composite material, and the composite material with the interface of any shape can be analyzed.
Disclosure of Invention
The invention aims to provide a thermal performance analysis method of a composite material with a curved interface, and a mathematical model and a numerical simulation method are established by solving the problem that a two-dimensional composite material has the curved interface type. The method can conveniently and quickly predict the temperature change of the inner side and the outer side of the composite material, so that the heat conduction performance of the composite material can be evaluated.
In order to solve the technical problems, the following technical means are adopted:
a method for thermal analysis of a composite material having a curvilinear interface, comprising the steps of:
s 1: analyzing the actual physical process of the multilayer heat transfer problem, and carrying out analysis and reasonable assumption by multiple models:
firstly, a material model with two layers of different media is considered, and the different materials have clear interfaces; for convenience, the problem of constant heat transfer is not considered, namely the temperature reaches a stable state in the transfer process of the composite material, and the absorption of the material to heat is neglected;
assuming that the material in each layer is isotropic and uniformly distributed, the three-dimensional model can be considered by simplifying the three-dimensional model into a two-dimensional problem along the thickness direction (vertical direction) of the material;
based on the above analysis and assumptions, the problem under study can be reduced to a two-dimensional thermal conduction problem, which is characterized as follows:
(a) consists of two substances, each two layers having distinct interfaces;
(b) the physical quantity at the material interface is interrupted;
(c) the temperature is transferred from outside to inside and from high to low;
carrying out numerical simulation on the steady-state heat conduction process of the composite material with the curve interface; interlayers of different materials are regarded as non-ideal interfaces through reasonable mathematical assumptions, and relevant interface connection conditions are proposed aiming at the characteristic that the physical properties on the interfaces are discontinuous; and converting the actual physical problem into a mathematical problem to solve.
: a mathematical description and control equation describing the heat transfer process of the multilayer material is given:
(a) two-dimensional problem the steady-state heat conduction process inside different media can be described by the following diffusion equation:
Figure 100002_RE-DEST_PATH_IMAGE001
(1)
Figure 100002_RE-RE-DEST_PATH_IMAGE002
(2)
wherein
Figure 100002_RE-DEST_PATH_IMAGE003
And is
Figure 100002_RE-RE-DEST_PATH_IMAGE004
Is a given function;
(b) interface between different media
Figure 100002_RE-DEST_PATH_IMAGE005
The jump and the discontinuity can occur, and the following connection conditions are adopted for depiction:
Figure 100002_RE-RE-DEST_PATH_IMAGE006
(3)
Figure 100002_RE-DEST_PATH_IMAGE007
(4)
wherein
Figure 100002_RE-RE-DEST_PATH_IMAGE008
Is an interface
Figure 100002_RE-DEST_PATH_IMAGE009
In a region
Figure 100002_RE-RE-DEST_PATH_IMAGE010
The unit of upper outer normal direction,
Figure 100002_RE-DEST_PATH_IMAGE011
representing the jump value of the variable at the interface,
Figure 100002_RE-RE-DEST_PATH_IMAGE012
and
Figure 100002_RE-DEST_PATH_IMAGE013
respectively represent temperature
Figure 100002_RE-RE-DEST_PATH_IMAGE014
At the interface
Figure 100002_RE-DEST_PATH_IMAGE015
Limits on both sides, i.e.
Figure 100002_RE-RE-DEST_PATH_IMAGE016
Figure 100002_RE-DEST_PATH_IMAGE017
And
Figure RE-RE-DEST_PATH_IMAGE018
respectively representing diffusion coefficients of media on two sides of the interface;
the equation (3) establishes the relationship between the temperatures of the left and right sides of the interface, and the temperature jumps of the two sides of the interface can be seen to be the sumThe heat flux across the interface is proportional with a proportionality coefficient of
Figure 100002_RE-DEST_PATH_IMAGE019
As can be seen from equation (4), the heat flow is equal across the interface, i.e., no heat is absorbed or generated at the interface.
: according to the parameters, thickness and heat conduction coefficient characteristics of the interlayer material, providing interface boundary conditions for describing discontinuous conditions of physical quantities on the interlayer;
dividing jump condition on interface into two parts along coordinate axis
Figure 100002_RE-RE-DEST_PATH_IMAGE020
And
Figure 100002_RE-DEST_PATH_IMAGE021
memory for recording
Figure 100002_RE-RE-DEST_PATH_IMAGE022
Is unit normal vector along the interface
Figure 100002_RE-DEST_PATH_IMAGE023
Point of direction
Figure 100002_RE-RE-DEST_PATH_IMAGE024
And is and
Figure 100002_RE-DEST_PATH_IMAGE025
the tangent vector on the interface can be expressed as
Figure 100002_RE-RE-DEST_PATH_IMAGE026
Then the jump condition on the interface can be re-expressed as
Figure 100002_RE-DEST_PATH_IMAGE027
(5)
Figure RE-DEST_PATH_IMAGE028
(6)
Jump of physical quantity on interface
Figure 100002_RE-DEST_PATH_IMAGE029
In the tangential direction can be expressed as,
Figure 100002_RE-RE-DEST_PATH_IMAGE030
(7)
wherein
Figure 100002_RE-DEST_PATH_IMAGE031
(8)
The formula (6) can be represented as
Figure 100002_RE-RE-DEST_PATH_IMAGE032
(9)
Similarly, the formula (7) can be represented as
Figure 100002_RE-DEST_PATH_IMAGE033
(10)
Multiplying equation (10) by
Figure 100002_RE-RE-DEST_PATH_IMAGE034
To obtain
Figure 100002_RE-DEST_PATH_IMAGE035
Solving the following system of linear equations
Figure 100002_RE-RE-DEST_PATH_IMAGE036
Then the process of the first step is carried out,
Figure 100002_RE-DEST_PATH_IMAGE037
and
Figure 100002_RE-RE-DEST_PATH_IMAGE038
can be expressed as
Figure 100002_RE-DEST_PATH_IMAGE039
And
Figure 100002_RE-RE-DEST_PATH_IMAGE040
to pair
Figure 100002_RE-DEST_PATH_IMAGE041
And
Figure 100002_RE-RE-DEST_PATH_IMAGE042
about
Figure 100002_RE-DEST_PATH_IMAGE043
Can obtain
Figure 100002_RE-RE-DEST_PATH_IMAGE044
According to the control equation
Figure 100002_RE-DEST_PATH_IMAGE045
Therefore, the temperature of the molten metal is controlled,
Figure 100002_RE-RE-DEST_PATH_IMAGE046
: dispersing the heat conduction model of the multi-layer heat insulation material by adopting a mathematical method to obtain a dispersion linear equation set;
for the two-dimensional problem, a dynamic template mode is selected for format construction; dividing all grid nodes into two types according to the position relation between the interface position and the grid nodes: (1) regular grid points, namely selecting a five-point template, wherein all the grid points in the template are positioned on one side of a material interface; (2) selecting 7-point templates with grid points distributed on two sides of a material interface;
performing orthogonal mesh generation on the calculation area to obtain a calculation mesh; it is assumed that the finite difference format of equation (1) can be expressed as
Figure 100002_RE-DEST_PATH_IMAGE047
(11)
For regular grid points
For regular grid points, if the 5-point format is adopted for direct dispersion, the corresponding coefficient is
Figure 100002_RE-RE-DEST_PATH_IMAGE048
And is
Figure 100002_RE-DEST_PATH_IMAGE049
Truncation error of the format of
Figure 100002_RE-RE-DEST_PATH_IMAGE050
Figure 100002_RE-DEST_PATH_IMAGE051
For irregular grid points
For irregular grid points, 7-point template is adopted for constructing format
Figure 100002_RE-RE-DEST_PATH_IMAGE052
(12)
Then, adaptively finding 7 points in the template according to the geometric relationship of the interface, and unfolding the non-central point variable to the central point by a Taylor unfolding method; by utilizing the relationship between the decomposition and the derivative of the physical quantity on the interface, a relational expression that the unknown quantity on the grid points is respectively described by the single-side node of the interface can be obtained; finally, the expression of the truncation error is utilized and is required to satisfy
Figure 100002_RE-DEST_PATH_IMAGE053
(ii) a Further, the coefficient in the formula (12) can be found by adopting a undetermined coefficient method, and the construction process of the numerical value format is completed.
: solving the discrete linear equation set and analyzing the result;
the model and value formats are validated by a problem with an accurate solution.
The invention has the following beneficial effects:
firstly, the method can be used for carrying out high-precision rapid analysis on the heat conduction process and the heat resistance performance of a multi-layer composite material such as sandwich steel, a heat-resistant firewall and the like;
secondly, the method provided by the invention has no any limitation on the geometric shape of the interface, so that the numerical simulation can be carried out on the heat conduction process of the combined fitting with the curved edge interface with any shape;
thirdly, the invention of the patent adopts a computer numerical simulation method to research the thermal performance of the multilayer material, so that the invention is not limited by physical factors such as the type, the thickness and the like of the material and can be applied to the composite multilayer material made of any material;
fourthly, the method is simple and reliable, and when the material quality changes, only corresponding physical parameters need to be adjusted in a computer, so that the method is an economic and money-saving research method and can help research, develop and analyze projects to save cost and time.
Drawings
FIG. 1 is a schematic view of a composite model I with a curved outer interface according to the present invention.
FIG. 2 is a schematic representation II of the composite model of the present invention having an interface within a curve.
FIG. 3 is a schematic diagram of the three-dimensional isotropic problem simplified into a two-dimensional problem model I according to the present invention.
Fig. 4 is a schematic diagram of the three-dimensional isotropic problem simplified into a two-dimensional problem model II according to the present invention.
FIG. 5 is a template for the two-dimensional curve interface problem of the present invention.
FIG. 6 is a computational grid of the present invention.
FIG. 7 is a comparison of the numerical solution and the exact solution of the present invention.
FIG. 8 is a diagram illustrating an error of a numerical solution according to the present invention.
The number of the grids is 80 x 80,
Figure RE-RE-DEST_PATH_IMAGE054
the calculation error of time.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Problem analysis and model assumptions
First, consider a material model with two layers of different media with clear interfaces between the different materials, as shown in fig. 1 and 2:
for convenience, the problem of constant heat transfer is considered, namely the temperature reaches a stable state in the transfer process inside the composite material, and the absorption of the material to heat is neglected; assuming that the material within each layer is isotropic and uniformly distributed, the three-dimensional model can be considered by simplifying it into a two-dimensional problem along the thickness direction (vertical direction) of the material, as shown in fig. 3 and 4:
based on the above analysis and assumptions, the problem under study can be reduced to a two-dimensional thermal conduction problem, which is characterized as follows:
(a) consists of two substances, each two layers having distinct interfaces;
(b) the physical quantity at the material interface is interrupted;
(c) the temperature is transferred from outside to inside and from high to low;
the method provided by the invention carries out numerical simulation on the steady-state heat conduction process of the sandwich steel. The physical model of the sandwich steel material is shown in figure 1. Interlayers of different materials can be regarded as non-ideal interfaces through reasonable mathematical assumptions, and relevant interface connection conditions are provided aiming at the characteristic that physical properties on the interfaces are discontinuous. And converting the actual physical problem into a mathematical problem to solve. Since the steady-state heat conduction process is described by the second order partial differential equation (poisson equation). Therefore, the control equation of the physical problems of the heat transfer process and the heat resistance performance of the sandwich steel plate can be shown by the formulas (1) to (4). The dimensions and thermal conductivity of the sandwich steel plates are shown in table 1 below:
TABLE 1 parameters of different metallic materials
Figure RE-DEST_PATH_IMAGE055
Establishing a mathematical model
(a) Two-dimensional problem the steady-state heat conduction process inside different media is described by the following diffusion equation:
Figure RE-RE-DEST_PATH_IMAGE056
(1)
Figure RE-DEST_PATH_IMAGE057
(2)
wherein
Figure RE-RE-DEST_PATH_IMAGE058
And is
Figure RE-DEST_PATH_IMAGE059
Is a given function;
(b) interface between different media
Figure RE-RE-DEST_PATH_IMAGE060
The jump and the discontinuity can occur, and the following connection conditions are adopted for depiction:
Figure RE-DEST_PATH_IMAGE061
(3)
Figure RE-RE-DEST_PATH_IMAGE062
(4)
wherein
Figure RE-570873DEST_PATH_IMAGE008
Is an interface
Figure RE-160118DEST_PATH_IMAGE009
In a region
Figure RE-471013DEST_PATH_IMAGE010
Upper unit outer normal direction.
Figure RE-DEST_PATH_IMAGE011A
Representing the jump value of the variable at the interface.
Figure RE-538327DEST_PATH_IMAGE012
And
Figure RE-759223DEST_PATH_IMAGE013
respectively represent temperature
Figure RE-378424DEST_PATH_IMAGE014
At the interface
Figure RE-287867DEST_PATH_IMAGE015
Limits on both sides, i.e.
Figure RE-283505DEST_PATH_IMAGE016
Figure RE-358908DEST_PATH_IMAGE017
And
Figure RE-86693DEST_PATH_IMAGE018
respectively representing diffusion coefficients of media on two sides of the interface;
equation (3) establishes the relationship between the temperatures of the left and right sides of the interface, and it can be seen that the temperature jumps of the two sides of the interface are proportional to the heat flux passing through the interface, and the proportionality coefficient is
Figure RE-372181DEST_PATH_IMAGE019
As can be seen from equation (4), heat flow throughThe sides of the interface are equal, i.e., no heat is absorbed or generated at the interface.
Decomposition and derivative relationships at curvilinear interfaces
First, a jump condition on an interface is divided into two parts along a coordinate axis
Figure RE-DEST_PATH_IMAGE063
And
Figure RE-RE-DEST_PATH_IMAGE064
memory for recording
Figure RE-DEST_PATH_IMAGE065
Is unit normal vector along the interface
Figure RE-RE-DEST_PATH_IMAGE066
Point of direction
Figure RE-DEST_PATH_IMAGE067
And is and
Figure RE-RE-DEST_PATH_IMAGE068
(ii) a The tangent vector on the interface can be expressed as
Figure RE-DEST_PATH_IMAGE069
(ii) a Then the jump condition on the interface may be re-expressed as
Figure RE-92881DEST_PATH_IMAGE027
(5)
Figure RE-RE-DEST_PATH_IMAGE070
(6)
Jump of physical quantity on interface
Figure RE-DEST_PATH_IMAGE071
In the tangential direction can be expressed as,
Figure RE-RE-DEST_PATH_IMAGE072
(7)
wherein
Figure RE-DEST_PATH_IMAGE073
(8)
The formula (6) can be represented as
Figure RE-819529DEST_PATH_IMAGE032
(9)
Similarly, the formula (7) can be represented as
Figure RE-RE-DEST_PATH_IMAGE074
(10)
Multiplying equation (10) by
Figure RE-187056DEST_PATH_IMAGE017
To obtain
Figure RE-336671DEST_PATH_IMAGE035
Solving the following system of linear equations
Figure RE-DEST_PATH_IMAGE075
Then the process of the first step is carried out,
Figure RE-RE-DEST_PATH_IMAGE076
and
Figure RE-DEST_PATH_IMAGE077
can be expressed as
Figure RE-80636DEST_PATH_IMAGE039
And
Figure RE-RE-DEST_PATH_IMAGE078
to pair
Figure RE-661790DEST_PATH_IMAGE076
And
Figure RE-403481DEST_PATH_IMAGE077
about
Figure RE-DEST_PATH_IMAGE079
Can obtain
Figure RE-RE-DEST_PATH_IMAGE080
According to the control equation
Figure RE-DEST_PATH_IMAGE081
Therefore, the temperature of the molten metal is controlled,
Figure RE-RE-DEST_PATH_IMAGE082
discrete equations and constructs numerical formats
For the two-dimensional problem, a dynamic template mode is selected for format construction. Dividing all grid nodes into two types according to the position relation between the interface position and the grid nodes, (1) regular grid points, selecting a five-point template, wherein all the grid points in the template are positioned at one side of a material interface; (2) and (4) selecting 7-point templates with irregular points, wherein grid points in the templates are distributed on two sides of the material interface, as shown in figure 5.
The calculation grid can be obtained by performing orthogonal grid division on the calculation region as shown in fig. 6. It is assumed that the finite difference format of equation (1) can be expressed as
Figure RE-DEST_PATH_IMAGE083
(11)
4.1 regular grid points
For regular grid points, if the 5-point format is adopted for direct dispersion, the corresponding coefficient is
Figure RE-RE-DEST_PATH_IMAGE084
And is
Figure RE-DEST_PATH_IMAGE085
Truncation error of the format of
Figure RE-RE-DEST_PATH_IMAGE086
Figure RE-DEST_PATH_IMAGE087
4.2 irregular grid points
For irregular grid points, 7-point template is adopted for constructing format
Figure RE-381670DEST_PATH_IMAGE052
(12)
Then, 7 points in the template are found in a self-adaptive mode according to the geometric relation of the interface, and the non-central point variable is expanded to the central point through a Taylor expansion method. And by using the relationship between the decomposition and the derivative of the physical quantity on the interface, a relational expression that the unknown quantity on the grid points is respectively described by the single-side node of the interface can be obtained. Finally, substituting the expression of 7 points in the template into the expression (12) and requiring that the truncation thereof meets the requirement of error
Figure RE-RE-DEST_PATH_IMAGE088
. Further, the coefficient in the equation (12) can be found by the undetermined coefficient method. Thus, the construction process of the numerical value format is completed.
(5) Solving the system of equations and analyzing the results
The model and value formats are first validated by a problem with an accurate solution. As can be seen from Table 2, the algorithm proposed in the present study can accurately simulate the temperature discontinuity and jump conditions on both sides of the interface, and the error is continuously reduced with the increase of the grid number, and the approximate second-order precision is maintained. The computational grid when the interface is circular is given from fig. 6. Figure 7 shows that the numerical solution matches the exact solution very well figure 8 gives the error of the numerical solution, and it can be seen that the error decreases as the number of grids increases.
Example 2 consider a calculation region of
Figure RE-DEST_PATH_IMAGE089
The interface position satisfies the condition
Figure RE-RE-DEST_PATH_IMAGE090
By dividing the area into two parts, an accurate solution to the problem can be given
Figure RE-DEST_PATH_IMAGE091
Wherein the diffusion coefficient is
Figure RE-RE-DEST_PATH_IMAGE092
The heat flow on the interface satisfies the conservation condition
Figure RE-DEST_PATH_IMAGE093
Example 1 at different grid numbers
Figure RE-RE-DEST_PATH_IMAGE094
The error and the convergence order of the signal,
Figure RE-DEST_PATH_IMAGE095
TABLE 2
Figure RE-RE-DEST_PATH_IMAGE096
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims (1)

1.一种具有曲线界面的复合材料的热性能分析方法,其特征在于包括以下步骤:1. a thermal property analysis method of the composite material with curved interface is characterized in that comprising the following steps: s1:分析多层传热问题的实际物理过程,多模型进行分析和合理假设s1: Analysis of the actual physical process of multi-layer heat transfer problems, multi-model analysis and reasonable assumptions 首先,考虑具有两层不同介质的材料模型,不同材料之间具有清晰的界面;考虑定常传热问题,即温度在复合材料内部的传递过程中达到稳定状态,并忽略材料本身对热量的吸收;假设各层内材料各向同性且分布均匀,则三维模型可以沿着材料厚度方向简化为二维问题来考虑;First, consider a material model with two layers of different media, and there are clear interfaces between different materials; consider the problem of steady heat transfer, that is, the temperature reaches a stable state during the transfer process inside the composite material, and the absorption of heat by the material itself is ignored; Assuming that the materials in each layer are isotropic and uniformly distributed, the 3D model can be simplified as a 2D problem along the material thickness direction; 根据以上的分析和假设,可以将研究的问题简化为二维导热问题,其特征如下:According to the above analysis and assumptions, the research problem can be simplified to a two-dimensional thermal conduction problem, which is characterized as follows: (a) 由两种物质组成,每两层之间明显的界面;(a) consists of two substances with a distinct interface between each two layers; (b) 在物质界面上的物理量发生间断;(b) discontinuities in physical quantities at the interface of matter; (c) 温度由外到内,由高到低传递;(c) The temperature is transferred from outside to inside, from high to low; 对曲线界面的复合材料的稳态导热过程进行数值模拟;不同材质之间的夹层通过数学假设看做是非理想界面,并针对界面上的物理性质不连续的特点,提出相关的界面连接条件;把实际物理问题转化为数学问题进行求解;The steady-state thermal conduction process of the composite material with the curved interface is numerically simulated; the interlayer between different materials is regarded as a non-ideal interface through mathematical assumptions, and the relevant interface connection conditions are proposed according to the discontinuous physical properties of the interface; Convert practical physical problems into mathematical problems to solve; s2:给出描述多层材料传热过程的数学描述及控制方程:s2: The mathematical description and governing equations describing the heat transfer process of multilayer materials are given: (a)二维问题不同介质内部的稳态热传导过程由以下扩散方程来描述:(a) Two-dimensional problem The steady-state heat conduction process inside different media is described by the following diffusion equation:
Figure RE-DEST_PATH_IMAGE001
(1)
Figure RE-DEST_PATH_IMAGE001
(1)
Figure RE-RE-DEST_PATH_IMAGE002
(2)
Figure RE-RE-DEST_PATH_IMAGE002
(2)
其中
Figure RE-DEST_PATH_IMAGE003
Figure RE-RE-DEST_PATH_IMAGE004
是给定的函数;
in
Figure RE-DEST_PATH_IMAGE003
and
Figure RE-RE-DEST_PATH_IMAGE004
is the given function;
(b) 在不同介质间的交界面
Figure RE-DEST_PATH_IMAGE005
上会发生跳跃和间断,采用如下的连接条件进行刻画:
(b) Interface between different media
Figure RE-DEST_PATH_IMAGE005
There will be jumps and discontinuities on the , which are characterized by the following connection conditions:
Figure RE-RE-DEST_PATH_IMAGE006
(3)
Figure RE-RE-DEST_PATH_IMAGE006
(3)
Figure RE-DEST_PATH_IMAGE007
(4)
Figure RE-DEST_PATH_IMAGE007
(4)
其中
Figure RE-RE-DEST_PATH_IMAGE008
为界面
Figure RE-DEST_PATH_IMAGE009
在区域
Figure RE-RE-DEST_PATH_IMAGE010
上的单位外法线方向;
Figure RE-DEST_PATH_IMAGE011
表示变量在界面处的跳跃值;
Figure RE-RE-DEST_PATH_IMAGE012
Figure RE-DEST_PATH_IMAGE013
分别表示温度
Figure RE-RE-DEST_PATH_IMAGE014
在界面
Figure RE-DEST_PATH_IMAGE015
两侧的极限值,即
in
Figure RE-RE-DEST_PATH_IMAGE008
for the interface
Figure RE-DEST_PATH_IMAGE009
in the area
Figure RE-RE-DEST_PATH_IMAGE010
The unit out-of-unit normal direction on ;
Figure RE-DEST_PATH_IMAGE011
Represents the jump value of the variable at the interface;
Figure RE-RE-DEST_PATH_IMAGE012
and
Figure RE-DEST_PATH_IMAGE013
respectively the temperature
Figure RE-RE-DEST_PATH_IMAGE014
in the interface
Figure RE-DEST_PATH_IMAGE015
the limit values on both sides, i.e.
Figure RE-RE-DEST_PATH_IMAGE016
Figure RE-RE-DEST_PATH_IMAGE016
Figure RE-DEST_PATH_IMAGE017
Figure RE-DEST_PATH_IMAGE018
分别表示界面两侧介质的扩散系数;
Figure RE-DEST_PATH_IMAGE017
and
Figure RE-DEST_PATH_IMAGE018
respectively represent the diffusion coefficients of the medium on both sides of the interface;
式(3)建立了界面上左右两侧温度的关系,可以看出界面两侧温度的跳跃是和穿过界面的热流量成比例,比例系数为
Figure RE-DEST_PATH_IMAGE019
;从式(4)中可以看出,热流穿过界面两侧相等,即界面上并不会吸收或产生热量;
Equation (3) establishes the relationship between the temperature on the left and right sides of the interface. It can be seen that the temperature jump on both sides of the interface is proportional to the heat flow through the interface, and the proportionality coefficient is
Figure RE-DEST_PATH_IMAGE019
; It can be seen from formula (4) that the heat flow through the interface is equal on both sides, that is, the interface does not absorb or generate heat;
s3:根据对夹层材料的参数和厚度、热传导系数特点,提出描述夹层上物理量不连续条件的界面边界条件;s3: According to the characteristics of the parameters, thickness and thermal conductivity of the interlayer material, the interface boundary condition describing the physical quantity discontinuity condition on the interlayer is proposed; 将界面上的跳跃条件沿着坐标轴分为两个部分
Figure RE-RE-DEST_PATH_IMAGE020
Figure RE-DEST_PATH_IMAGE021
,记
Figure RE-RE-DEST_PATH_IMAGE022
为界面上的单位法向量沿着
Figure RE-DEST_PATH_IMAGE023
指向
Figure RE-RE-DEST_PATH_IMAGE024
,且
Figure RE-DEST_PATH_IMAGE025
;界面上的切向量可以表示为
Figure RE-RE-DEST_PATH_IMAGE026
;那么界面上的跳跃条件可以重新表示为
Divide the jump condition on the interface into two parts along the coordinate axis
Figure RE-RE-DEST_PATH_IMAGE020
and
Figure RE-DEST_PATH_IMAGE021
,remember
Figure RE-RE-DEST_PATH_IMAGE022
is the unit normal vector on the interface along
Figure RE-DEST_PATH_IMAGE023
direction
Figure RE-RE-DEST_PATH_IMAGE024
,and
Figure RE-DEST_PATH_IMAGE025
; the tangent vector on the interface can be expressed as
Figure RE-RE-DEST_PATH_IMAGE026
; then the jump condition on the interface can be re-expressed as
Figure RE-DEST_PATH_IMAGE027
(5)
Figure RE-DEST_PATH_IMAGE027
(5)
Figure RE-RE-DEST_PATH_IMAGE028
(6)
Figure RE-RE-DEST_PATH_IMAGE028
(6)
物理量在界面上的跳跃
Figure RE-DEST_PATH_IMAGE029
沿切向方向可以表示为,
The jump of physical quantity on the interface
Figure RE-DEST_PATH_IMAGE029
Along the tangential direction can be expressed as,
Figure RE-RE-DEST_PATH_IMAGE030
(7)
Figure RE-RE-DEST_PATH_IMAGE030
(7)
其中in
Figure RE-DEST_PATH_IMAGE031
(8)
Figure RE-DEST_PATH_IMAGE031
(8)
式(6)可以表示为Equation (6) can be expressed as
Figure RE-RE-DEST_PATH_IMAGE032
(9)
Figure RE-RE-DEST_PATH_IMAGE032
(9)
同理,式(7)可以表示为Similarly, formula (7) can be expressed as
Figure RE-DEST_PATH_IMAGE033
(10)
Figure RE-DEST_PATH_IMAGE033
(10)
将式(10)乘以
Figure RE-RE-DEST_PATH_IMAGE034
,得到
Multiply equation (10) by
Figure RE-RE-DEST_PATH_IMAGE034
,get
Figure RE-DEST_PATH_IMAGE035
Figure RE-DEST_PATH_IMAGE035
求解如下的线性方程组Solve the following system of linear equations
Figure RE-RE-DEST_PATH_IMAGE036
Figure RE-RE-DEST_PATH_IMAGE036
则,
Figure RE-DEST_PATH_IMAGE037
Figure RE-RE-DEST_PATH_IMAGE038
可以表示为
but,
Figure RE-DEST_PATH_IMAGE037
and
Figure RE-RE-DEST_PATH_IMAGE038
It can be expressed as
Figure RE-DEST_PATH_IMAGE039
Figure RE-DEST_PATH_IMAGE039
and
Figure RE-RE-DEST_PATH_IMAGE040
Figure RE-RE-DEST_PATH_IMAGE040
Figure RE-DEST_PATH_IMAGE041
Figure RE-RE-DEST_PATH_IMAGE042
关于
Figure RE-DEST_PATH_IMAGE043
可以得到
right
Figure RE-DEST_PATH_IMAGE041
and
Figure RE-RE-DEST_PATH_IMAGE042
about
Figure RE-DEST_PATH_IMAGE043
can get
Figure RE-RE-DEST_PATH_IMAGE044
Figure RE-RE-DEST_PATH_IMAGE044
根据控制方程可得According to the control equation, we can get
Figure RE-DEST_PATH_IMAGE045
Figure RE-DEST_PATH_IMAGE045
因此,therefore,
Figure RE-RE-DEST_PATH_IMAGE046
Figure RE-RE-DEST_PATH_IMAGE046
s4:采用数学方法对多层隔热材料导热模型进行离散,得到离散线性方程组;s4: Use mathematical methods to discretize the thermal conductivity model of the multi-layer thermal insulation material to obtain a discrete linear equation system; 对于二维问题,选择动态模板的方式进行格式构造;根据界面位置与网格节点的位置关系将所有的网格节点分为两类: (1) 规则网格点,选择五点模板,且模板中的所有网格点都在物质界面的一侧;(2) 非规则点,选择7点模板,且模板中的网格点分布在物质界面的两侧;For the two-dimensional problem, the dynamic template is selected for format construction; all grid nodes are divided into two categories according to the positional relationship between the interface position and the grid node: (1) For regular grid points, choose a five-point template, and the template All grid points in are on one side of the material interface; (2) For irregular points, select a 7-point template, and the grid points in the template are distributed on both sides of the material interface; 对计算区域进行正交网格剖分,可以得到计算网格;假设方程(1)的有限差分格式可以表示为The calculation grid can be obtained by orthogonal meshing of the calculation area; it is assumed that the finite difference scheme of equation (1) can be expressed as
Figure RE-DEST_PATH_IMAGE047
(11)
Figure RE-DEST_PATH_IMAGE047
(11)
对于规则网格点For regular grid points 对于规则网格点,采用5点格式直接离散,则其相对应的系数为For regular grid points, the 5-point format is used for direct discretization, and the corresponding coefficient is
Figure RE-RE-DEST_PATH_IMAGE048
Figure RE-RE-DEST_PATH_IMAGE048
and
Figure RE-DEST_PATH_IMAGE049
Figure RE-DEST_PATH_IMAGE049
格式的截断误差为
Figure RE-RE-DEST_PATH_IMAGE050
The truncation error of the format is
Figure RE-RE-DEST_PATH_IMAGE050
:
Figure RE-DEST_PATH_IMAGE051
Figure RE-DEST_PATH_IMAGE051
对于非规则网格点For irregular grid points 对于非规则网格点,采用7点模板进行构造格式For irregular grid points, use 7-point template for construction format
Figure RE-RE-DEST_PATH_IMAGE052
(12)
Figure RE-RE-DEST_PATH_IMAGE052
(12)
然后根据界面的几何关系自适应找到模板中的7个点,并且将非中心点变量通过Taylor展开方法进行展开到中心点处;并利用界面上物理量的分解和导数的关系,可以得到网格点上的未知量分别由界面单侧节点进行描述的关系式,得到相应的关系式;最后,利用截断误差的表达式,并要求其满足
Figure RE-DEST_PATH_IMAGE053
;进而,采用待定系数法,就可以找到(12)式中的系数,完成数值格式的构造过程;
Then, according to the geometric relationship of the interface, 7 points in the template are found adaptively, and the non-center point variables are expanded to the center point by the Taylor expansion method; and the relationship between the decomposition of the physical quantities on the interface and the derivative can be used to obtain the grid points The unknowns on the interface are described by the relational expressions on one side of the interface, respectively, and the corresponding relational expressions are obtained; finally, the expression of the truncation error is used, and it is required to satisfy
Figure RE-DEST_PATH_IMAGE053
; Furthermore, by using the undetermined coefficient method, the coefficients in the formula (12) can be found, and the construction process of the numerical format can be completed;
s5:对离散线性方程组进行求解,并分析结果;s5: Solve the system of discrete linear equations and analyze the results; 通过具有精确解的问题对模型和数值格式进行验证。Validate models and numerical formats with problems with exact solutions.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112036039A (en) * 2020-09-01 2020-12-04 内蒙古科技大学 A high-precision numerical analysis method for thermal properties of conjugated heat transfer materials

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2769167A1 (en) * 1997-09-29 1999-04-02 Centre Nat Rech Scient REINFORCED SUPERCONDUCTING MATERIAL, SUPERCONDUCTIVE CAVITY, AND METHODS OF MAKING
WO2008112013A1 (en) * 2006-10-04 2008-09-18 The Regents Of The University Of California Carbon nanotube arrays as thermal interface materials
CN109564786A (en) * 2016-08-08 2019-04-02 通用原子公司 Engineering SIC-SIC composite material and entirety SIC layer structure
CN109926675A (en) * 2019-03-29 2019-06-25 安徽双桦热交换系统有限公司 A kind of NB continous way soldering core heating means of Soldering Technology of Automobile Radiators

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2769167A1 (en) * 1997-09-29 1999-04-02 Centre Nat Rech Scient REINFORCED SUPERCONDUCTING MATERIAL, SUPERCONDUCTIVE CAVITY, AND METHODS OF MAKING
WO2008112013A1 (en) * 2006-10-04 2008-09-18 The Regents Of The University Of California Carbon nanotube arrays as thermal interface materials
CN109564786A (en) * 2016-08-08 2019-04-02 通用原子公司 Engineering SIC-SIC composite material and entirety SIC layer structure
CN109926675A (en) * 2019-03-29 2019-06-25 安徽双桦热交换系统有限公司 A kind of NB continous way soldering core heating means of Soldering Technology of Automobile Radiators

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
万长风;林继;洪永兴;: "边界节点法模拟瞬态热传导及Matlab工具箱开发", 能源与环保, no. 02 *
张程宾;韩群;陈永平;: "基于MATLAB的传热学课程虚拟仿真实验平台设计", 实验技术与管理, no. 01 *
石琳;程素森;阮新伟;许良友;: "高炉铸铜冷却壁的热性能分析", 钢铁, no. 06 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112036039A (en) * 2020-09-01 2020-12-04 内蒙古科技大学 A high-precision numerical analysis method for thermal properties of conjugated heat transfer materials
CN112036039B (en) * 2020-09-01 2022-12-23 内蒙古科技大学 A high-precision numerical analysis method for thermal properties of conjugated heat transfer materials

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