CN104809269A - Heat transfer simulation method based on fabric geometric structure - Google Patents

Abstract

The invention discloses a heat transfer simulation method based on the fabric geometric structure. According to the heat transfer simulation method based on the fabric geometric structure, a fabric three-dimensional simulation model is built according to fabric parameters, the fabric model is simulated with a finite element method, and the characteristic that the temperature in fabric in the heated state changes along with time is simulated. Due to the heat transfer simulation method based on the fabric geometric structure, fabric transfer simulation becomes simple, and in the simulation process, the changes of the temperature in the fabric along with time can be obtained just by inputting the characteristics of the fabric material and a simulated environment. Compared with the existing simulation methods, the heat transfer simulation method based on the fabric geometric structure is on the basis of the real structure of the fabric, the defect that fabric is simplified to a homogeneous panel is overcome, and under the same conditions, the simulation result coincides with an experiment result. A fabric heat transfer image simulated with the method is very real, and the method is simple. Through the heat transfer simulation method based on the fabric geometric structure, the real structure of the fabric can be shown.

Description

Based on the Heat Transfer Simulation method of geometry of deth

Technical field

The present invention relates to computer modeling technique, be specifically related to a kind of Heat Transfer Simulation method based on geometry of deth.

Background technology

In investigation of materials field, mainly tested acquisition by experiment to the research of material behavior, the data obtained are comprehensively reliable, can reflect the character of material really in the past.Such as, but this method of experiment test that utilizes merely exists many weak points, needs the experiment material of at substantial, carry out that a large amount of to repeat experiment consuming time more, some test can produce noxious material, and harmful gas impacts environment.Along with the development of computer technology and the exploitation of finite element analysis software, utilize computing machine to build model, carrying out analyzes and researches becomes new focus.This research mode has saved time and cost, can raise the efficiency, and is optimized after utilizing computing machine Fast simulation to experiment parameter, has very strong practical value and realistic meaning.

Just start to solve problem at field of textiles application finite element analysis technology as far back as the eighties in 20th century, what initial Application comparison was many is carry out structure mechanics analysis to textile machine, along with the development of finite element technique, applied to the analysis of the flexible material such as fabric, yarn afterwards gradually.

The fabric heat transfer model of current research is mostly under being based upon two-dimensional direct angle coordinate system, fabric unit is reduced to homogeneous flat board or right cylinder, modeling difficulty can be reduced like this, but also lose the real institutional framework of fabric, have influence on the degree of accuracy of numerical simulation.

Summary of the invention

For the deficiencies in the prior art, the technical matters that quasi-solution of the present invention is determined is, provides a kind of Heat Transfer Simulation method based on geometry of deth.Object solves because cloth simulation precision is not high, fidelity inadequate, thus cause the not high series of technical of textile simulating modeling effort aspect accuracy.

For achieving the above object, the technical solution used in the present invention is:

Based on the Heat Transfer Simulation method of geometry of deth, comprise the steps:

Obtain the performance parameter treating simulate fabric; Comprise fabric thickness, coefficient of heat conductivity, specific heat capacity; Wide, high and spacing, the fibre diameter of yarn.Fabric thickness is obtained according to GB/T 7689.1-2013 standard digital textile thickness gauge; Coefficient of heat conductivity and the specific heat capacity of fabric is obtained by thermal constant analyser; The wide, high of yarn and spacing is obtained by SEM; Optical microscope is utilized to obtain fibre diameter.

The present invention gives tacit consent to yarn cross section for oval, characterizes with following formula:

${C\left(t\right)}_x=\frac{\mathrm{\ω}}{2}\cos \left(2\mathrm{\πt}\right)0\≤t\≤1$

${C\left(t\right)}_y=\frac{h}{2}\sin \left(2\mathrm{\πt}\right)0\≤t\≤1---\left(1\right)$

In formula: ω is yarn cross section width; H is yarn cross section height; T is yarn node.According to Fabric Property Parameter, build the three-dimensional geometrical structure model of fabric.

This model is imported to finite element software ABAQUS;

Model is applied to temperature loading, carries out thermal analyses to stream loading;

Carry out computer solving, obtain temperature variation cloud atlas and temperature rise data in fabric.

The present invention is owing to adopting above technical scheme, and it has following characteristics:

1. characterize yarns interwoven state in fabric accurately.

2. simulate the temperature variation in fabric under heating status accurately.

Accompanying drawing explanation

Fig. 1 regards homogeneous flat board as fabric when being conventional heat transfer simulation.

Fig. 2 is the cloth modeling figure that the present invention is based on a kind of plain weave embodiment that geometry of deth builds.

Fig. 3 is the fabric model heat transfer distribution schematic diagram of an embodiment of the present invention.

Fig. 4 is the analog result figure of an embodiment of the present invention, wherein fabric is considered as model configuration that homogeneous flat board obtains and experimental result data comparison diagram by (a), and (b) is based on geometry of deth analog result and experimental result data comparison diagram.

Embodiment

The present invention is described further below in conjunction with embodiment 1, embodiment 2 and accompanying drawing thereof.

As shown in Figure 2, this example 1 is geometry modeling and the analysis of Heat Transfer of fiberglass scrim.Step is as follows:

Step one: be the plain cloth of 100*120 by the fiberglass weaving density of 280tex.

Step 2: obtain fabric thickness according to GB/T 7689.1-2013 standard YG141L type digital textile thickness gauge; Coefficient of heat conductivity and the specific heat capacity of fabric is obtained by HOT DISK 2500S thermal constant analyser; The wide, high of yarn and spacing is obtained by SEM; Optical microscope is utilized to obtain fibre diameter.Test result is as shown in table 1.

Table 1 fabric and yarn parameter

Step 3: by the yarn width recorded in step 2, be highly updated in formula (1), calculates yarn cross section.Again by other parameters input in TexGen software, draw fabric tissue.

${C\left(t\right)}_x=\frac{\mathrm{\ω}}{2}\cos \left(2\mathrm{\πt}\right)0\≤t\≤1$

${C\left(t\right)}_y=\frac{h}{2}\sin \left(2\mathrm{\πt}\right)0\≤t\≤1---\left(1\right)$

In formula: ω is yarn cross section width; H is yarn cross section height; T is yarn node.

Step 4: will obtain fabric three-dimensional model and save as igs form and import in finite element software ABAQUS, for fabric adds coefficient of heat conductivity, specific heat capacity and density (2400kg.m ^-3) attribute.

In this example 1, experiment is that heating flame temperature is 830 DEG C to the heating of fabric one side alcohol blast burner, and record envers temperature climb data, conducts heat and temperature rise process in fabric under simulation simulated condition.

With finite element software, thermal analyses is carried out to fabric, and solve calculating fabric diabatic process, obtain temperature variation cloud atlas and temperature rise data in fabric.Simulate under fabric is considered as homogeneous dull and stereotyped condition, the diabatic process of equivalent environment fabric simultaneously.

In fabric, temperature variation cloud atlas as shown in Figure 3, and analog result and experimental result comparison diagram are as shown in Figure 4.Fig. 4 (a) contrasts for the model configuration that fabric is considered as homogeneous flat board and obtains and experimental result data, and Fig. 4 (b) contrasts based on geometry of deth analog result and experimental result data.The mean deviation that can be calculated traditional Heat Transfer Simulation method is 15%, and the result error that the present invention obtains is 5%, as seen based on geometry of deth analog result and experimental result more identical, simulation precision is apparently higher than classic method; And the simulation precision important indicator whether be method for numerical simulation feasible, therefore come simulate fabric heat transfer and tradition based on geometry of deth and fabric regarded as compared with the method for homogeneous flat board, there is obvious accuracy and advance.

Embodiment 2:

Embodiment 2 is the twill geometry modeling of glass fibre 3/1 and analysis of Heat Transfer.Step is as follows:

Step one: 3/1 twills by the fiberglass weaving density of 280tex being 100*120.

Step 2: obtain fabric thickness according to GB/T 7689.1-2013 standard YG141L type digital textile thickness gauge; Coefficient of heat conductivity and the specific heat capacity of fabric is obtained by HOT DISK 2500S thermal constant analyser; The wide, high of yarn and spacing is obtained by SEM; Optical microscope is utilized to obtain fibre diameter.Test result is as shown in table 2.

Table 2 fabric yarn parameter measurements

Step 3: by the yarn width recorded in step 2, be highly updated in formula (1), calculates yarn cross section.Again by other parameters input in TexGen software, draw fabric tissue.

${C\left(t\right)}_x=\frac{\mathrm{\ω}}{2}\cos \left(2\mathrm{\πt}\right)0\≤t\≤1$

${C\left(t\right)}_y=\frac{h}{2}\sin \left(2\mathrm{\πt}\right)0\≤t\≤1---\left(1\right)$

In formula: ω is yarn cross section width; H is yarn cross section height; T is yarn node.

Step 4: will obtain fabric three-dimensional model and save as igs form and import in finite element software ABAQUS, for fabric adds coefficient of heat conductivity, specific heat capacity and density (2400kg.m ^-3) attribute.

In this example 2, experiment is that heating flame temperature is 830 DEG C to the heating of fabric one side alcohol blast burner, and record envers temperature climb data, conducts heat and temperature rise process in fabric under simulation simulated condition.

With finite element software, thermal analyses is carried out to fabric, and solve calculating fabric diabatic process, obtain temperature variation cloud atlas and temperature rise data in fabric.Simulate under fabric is considered as homogeneous dull and stereotyped condition, the diabatic process of equivalent environment fabric simultaneously.

Simulate heat transfer according to above step to twills modeling, analog result and experimental result are contrasted and obtain, mean deviation is about 5%.Visible the present invention is applicable to various tissue fabric.Therefore, the diabatic process that the present invention can be between researching high-temperature environment yarn under working pilotaxitic texture provides new approaches, for the design of various fibrous thermal product, evaluating and optimizing etc. of heat-proof quality provide important theoretical foundation.

Claims (6)

1., based on the numerical method setting up geometry of deth and come heat transmit mode when simulate fabric is heated, it is characterized in that, the method comprises the following steps:

(1) performance parameter treating simulate fabric is obtained;

(2) according to this performance parameter, the three-dimensional stereo model of fabric is built;

(3) this model is imported to finite element software ABAQUS;

(4) model is applied to the load such as temperature and carry out thermal analyses;

(5) temperature variation cloud atlas and temperature rise data in fabric are obtained.

2. a kind of fabric heat trnasfer analogy method according to claim 1, is characterized in that: described fabric is glass fibre plain fabric.

3. a kind of fabric heat trnasfer analogy method according to claim 1, is characterized in that: described Fabric Property Parameter comprises fabric thickness, coefficient of heat conductivity, specific heat capacity; Wide, high and spacing, the fibre diameter of yarn.

4. a kind of fabric heat trnasfer analogy method according to claim 2, is characterized in that: described fabric parameter obtains in the following manner: obtain fabric thickness according to GB/T 7689.1-2013 standard digital textile thickness gauge; Coefficient of heat conductivity and the specific heat capacity of fabric is obtained by thermal constant analyser; The wide, high of yarn and spacing is obtained by SEM; Optical microscope is utilized to obtain fibre diameter.

5. a kind of fabric heat trnasfer analogy method according to claim 1, is characterized in that: flame temperature when described temperature loading is fabric heating.

6. a kind of fabric heat trnasfer analogy method according to claim 1, is characterized in that: described thermal analyses is Nonlinear Transient analysis.