Research On Heat And Moisture Transport Performance Of Fiber Porous Fabric Based On Drying Kinetics

With the deepening of the industrialization process,the fire protection work will face more severe tests.In-depth study of fire protection clothing has important practical value.In the four-layer structure of fire-fighting clothing,non-woven fiber porous fabric is often used as the material of the thermal insulation layer and has excellent thermal protection performance.After the heat insulation material is heated at high temperature,the latent heat of the moisture in the evaporation process will have a certain impact on the clothing.Therefore,studying the heat and moisture transport performance of non-woven fiber porous fabrics is beneficial to improve the thermal protection performance of fire-fighting clothing.At the same time,it is of great significance to the development and design of new firefighting clothing.In this paper,firstly,the porosity,surface porosity and average pore size of nine nonwoven fiber porous fabrics were obtained by mercury intrusion method and SEM image method,and the pore size and pore size distribution of each fabric were analyzed.At the same time,the relationship between the pore characteristic index porosity,surface porosity,average pore size and air permeability,moisture permeability and thermal resistance of the nonwoven fiber porous fabric is explored,and further research is made for the dynamic heat and moisture transfer process of the nonwoven fiber porous fabric.The results show that:(1)The air permeability of non-woven fiber porous fabrics is mainly related to surface porosity and average pore size.Among them,the air permeability of non-woven fiber porous fabrics with similar density and basis weight is related to surface porosity and average pore size.(2)The moisture permeability of the nine non-woven fiber porous fabrics is mainly related to the thickness and average pore size;(3)The thermal resistance of the nine non-woven fiber porous fabrics is mainly related to the thickness and average pore size The thermal resistance of the non-woven fiber porous fabric also increases as the thickness and average pore diameter increase.Secondly,the transient plane heat source method is used to measure the thermal conductivity of the nonwoven fiber porous fabric with different moisture content,analyze the influence of the moisture content on the thermal conductivity of the nonwoven fiber porous fabric,and use three different analysis fitting methods to study the moisture content.The relationship between rate and effective thermal conductivity.The results show that the thermal conductivity of the non-woven fiber porous fabric increases with the increase of the moisture content.Using univariate high-order polynomial regression analysis,the nonwoven fiber porous fabric with low actual moisture regain has a significant univariate highorder polynomial regression relationship;the series-parallel model verifies the experimental values measured by the experiment,and the experimental values and predictions of the five samples The value correlation is small;the improved series-parallel model determines the relationship between moisture content and thermal conductivity.Samples N1,N2,and N5 have a good fit,while samples N3 and N4 have a fair fit.Due to the pore structure of the fabric and the high performance of the fiber itself,it is also a process of continuous drying of the fabric during the measurement process.Finally,the experiment researched the temperature changes and surface characteristics of four kinds of non-woven fiber porous fabrics with different moisture content during flat plate drying,and explored the moisture distribution and evaporation process during lowtemperature heat conduction.At the same time,the drying characteristics and drying kinetic model fitting of two kinds of aramid nonwoven fiber porous fabrics under different heat radiation environments were studied when the moisture content was 15%.The results show that the drying process of the two samples under different radiant heat environments decreases.At the beginning,the drying rate is higher,and the drying time continues to increase,and the drying rate becomes smaller,and as the heat radiation intensity increases,the drying rate decreases.The more obvious the speed process is;the greater the influence of thermal radiation on the effective diffusion coefficient of water;the fitting analysis of the experimental model shows that the Logarithmic model has a greater correlation with the experimental value and is suitable for describing the non-water content of 15%.Drying process of woven fiber porous fabric under different heat radiation environment.