Simulation Of Heat And Moisture Coupling Of Porous Fabric Under Multiphase And Multicomponent State

The progress of science and technology drives the development in various fields,functionality of textiles have received more and more attention, especially the heat and moisture selection of fabric and batting, and the effect of external environment on heat and moisture coupling, which is as the starting point of this paper. The paper research the mutual influence of the solid phase,liquid phase and gas phase inside multiple layer fabric under different environmental conditions, which consist two components: covering and packing.The paper selects the fabric and batting, which is used widely. By using the advanced instrument of heat and moisture performance, test the parameters of heat and moisture performance. Under the same condition of external environment, explore the factors on the heat and moisture performance of multiple layer fabric. The experimental results show that: Compared with surface fabric, batting have bigger influence on the warmth of multiple layer fabric, but the latter is more outstanding in the permeability index;On the premise of similar specifications of fabric, the covering fabric with good permeability can the improve the moisture permeability of multilayer fabric; Increasing the yarn count and density of covering fabric, can improve the warmth of multi-layer fabric.In order to understand the mechanism of heat and moisture coupling of multiple layer fabric, the paper analyzes these from the perspective of numerical simulation and proposes a two-dimensional partial differential dynamic model of coupling heat and moisture. The model takes into account the effect of moisture absorption and desorption of fabric, the mechanism of condensation, conduction, convection and the complex heat and moisture transmission. Use the Dirichle boundary to define the model. Meanwhile, the paper carries out the discrete model based on finite difference method to improve the calculation accuracy. With the help of Matlab programming to solve the model, obtain the trend graph of relevant physical parameters varying with time and position, verify therationality of the model processing through comparative the analysis of simulation and experimental test, which include the water content and internal temperature.The paper simulate the absorbent of fibers, the water content inside the batting,the interior temperature of multiple layer fabric and changes of concentration of water vapor in the external conditions of different simulation. Simulation results show that: The increasing of relative humidity of environment is conductive to the increase of the concentration of water vapor inside the fiber and improving the peak of test point; Water content of polyester is higher than the wool, but absorption rate of wool is rapider, the maximum can reach 0.12, while the absorption of polyester fiber is negligible; With the reduction of relative humidity, temperature value internal multi-layer fabric will rise and the tendency of reducing will slow down; With the drop of external temperature,concentration of vapor inside multi-layer fabric will decreased at the same position along the direction of the skin-environment; When the relative humidity increases, reduce of concentration of vapor will be speeded up inside the multilayer fabric along direction of skin- environment.