Numerical Simulation Of Heat Transfer In Glass Fiber Fabrics

Numerical simulation technology belongs to the virtualization technology. Research on modeling and simulation of heat transfer about woven fabrics has been intensive for the past years. Traditional thermal protection materials are developed based on the environment of high temperature, which may increase the cost and then reduce the efficiency. And the application of numerical simulation technology in the textile area can the materials development more efficient. After the heat transfer model has been set up, the properties of the materials will be predict rapidly and economically, which can provide the theoretical basis for future research of fabric heat transfer analysis.In this paper, five different weave patterns (plain, hopsack,2/2 twill,3/3 twill and 5/3 satin fabrics) and two different double weave (double plain and double twill) were modeled based on the yarn path function and cross-sectional shapes; the physical properties of yarns and fabric were measured such as fabric thickness, thermal conductivity and yarn width. The results showed that, based on the physical structure parameters of yarns and the actual photos of fabrics, it was possible to create geometric model of fabric and the model could reflect the spatial structure of the yarn compared to the plate.The thermal analysis method was proposed in the paper. In the thermal analysis, the models were applied to the heat transfer simulation in which the fabrics were treated as a porous system due to the entrapped air. The yarn components and air components among the fabric can be defined respectively in the geometric model, and then the physical parameters of the fabric can be given successfully. The most important is the fabric system parts were in good contact. The temperature distributions of these fabrics about different heated time can be obtained after analysis. It was found that the temperature displayed a layered distribution inside the fabrics, which gradually decreased from the heated surface layer to the back layer. And the weave patterns and float lengths of the fabrics have a significant effect on heat transfer. The diversities between the different fabrics may be attributed mainly to the structure and corresponding entrapped air retained among the fibers of yarns, because the conductivity of air was much lower than that of glass fiber materials. Therefore, the ability of the fabric to insulate heat depended upon the tightness of the construction and the bulk of the yarns. A loose, open construction traps more still air among the yarns. However, the tightness of fabric relies largely on the length of floats within the fabric.The simulated results were validated against experimental data. Good comparisons with the experimental results demonstrate that the method of heat transfer analysis was applied to the coated fabric and oil pipeline insulation fabric. It was showed that the method for simulation can reflect the reality of the test results; it is also suggests that the numerical approach to predict the heat transfer of fabric is feasible and effective, which has practical value and economic value in the future.