Research On The Heat Transfer And Deformation Properties Of Carbon Fiber Fabric Under The Impact Of Heat Flow

In order to reduce or even eliminate heat damage caused by high temperature,it is crucial to study the heat transfer mechanism and process of fabric under heat flow.Firstly,the three-dimensional geometric model of carbon fiber fabric is established,and then the appropriate solution conditions are given for the environment of the fabric placed.Based on the basic theories of fluid mechanics,heat transfer and elasticity mechanics,the temperature distribution on the back of the fabric and the maximum deformation of the fabric are solved by finite element method.And the experimental platform is built to verify the feasibility of the numerical model.The conclusions are as follows:(1)The three-dimensional geometric model of carbon fiber fabrics based on yarn height,yarn width,yarn spacing,fabric thickness and cross-sectional shape can accurately reflect the structure of carbon fiber fabrics,which was in good agreement with the electron microscopic images.(2)When the heat flux was 1319 W/m2 and 1103 W/m2 respectively,the average relative errors of the simulated and experimental values of the back temperature of the fabric were 6.64%and 3.28%,respectively.It showed that the numerical model can reflect the dynamic heat transfer process of carbon fiber plain weave fabric.(3)Based on the basic principle of stress and deformation,the finite element method was used to calculate the stress and deformation of fabrics,and to predict the maximum deformation of fabrics under pressure.The maximum deformation of the fabrics calculated by simulation was 0.0017m,which was quite different from the experimental value of 0.036m.It was necessary to analyze the reasons and further improve the model.(4)A thermal-structural coupling analysis model between airflow and carbon fiber fabric was established.The finite element method was used to solve the temperature variation of the fabric back surface under the coupling effect.The results of thermal-structural coupling calculation and experiment were compared.It was found that the temperature distribution curve calculated by numerical simulation on the back side of the fabric was consistent with the experimental test temperature curve in the overall trend.The simulated value of fabric back temperature was 49.30 ? and the experimental value was 46.16 ? when the fabric was in equilibrium,and the difference between them was not significant.(5)The thermal-structural coupling analysis model between air flow and carbon fiber fabric was established,and the maximum deformation of the fabric under the coupling effect was calculated by finite element method.Comparing the calculation results of the thermal-structural coupling of the fabric and the experimental results,the simulated maximum value of the fabric was 3.46×10-2 m,and the maximum deformation of the fabric was 3.6×10-2 m,and the relative error was 3.8%.The established fabric thermal-structural coupling model can predict the maximum deformation of the fabric under external loads.