Inverse Problems Of Optimal Textile Porosity Det-Ermination Under Low Temperature

The design of functional textile materials aims to determine their physical and geo-metrical parameters according to the requirements of comfort,warmth,etcetera,so as to optimize the performance of textiles and provide theoretical basis and scientific reference for garment manufacturers.In this paper,based principally on a dynamic coupled model of heat and moisture transfer within textile under low temperature and its properties of warm and permeability,inverse problems of porosity determination for single-layer and multi-layer textiles are proposed.The corresponding functional expressions are put forward and the numerical algorithms for solving those are applied.This article is mainly composed of the following parts:In the first chapter,the background and significance of domestic and abroad researches on textile,as well as the contents and results of previous research,are described.In the second chapter,based on the existing heat and moisture transfer model within single-layer textile under low temperature,the original first-type boundary conditions are improved into the third-type,which take the heat and moisture transfer in the midst of the human skin,outer environment and the fabric into account.The explicit-implicit finite difference scheme is employed to obtain the numerical solution.Additionally,a ghost point is introduced on the boundary conditions to enhance the accuracy of numerical solution.Then the existence and uniqueness,stability and convergency of the model are analyzed by the energy equation theory.Finally,the numerical simulation is given,and the result is in accordance with the actual situation,which indicate that the model is rational.In the third chapter,on the basis of the improved single-layer model in Chapter Two,the heat and moisture transfer model is extended to the multi-layer,of which the appropriate boundary conditions between layers are presented.For starters,a dynamic model of heat and moisture transfer within multi-layer textiles is given.In addition,a model with bi-layer textiles is numerically calculated by the explicit-implicit finite difference scheme.Likewise,a ghost point is introduced on the boundary conditions so as to improve the precision of numerical solution.Moreover,the existence and uniqueness,stability and convergency of the corresponding numerical solution are proved.At last,two numerical examples are given to illustrate different materials will have effect on the heat and moisture transfer of textile.In the fourth chapter,for the purpose of the best warm and permeability within textile under low temperature,inverse problems of porosity determination in single-layer and multi-layer textiles are put forward.The permeability index is applied to measure the warm and permeability of textile in this paper.Consequently,the corresponding optimization function for inverse problems can be posed,which is simulated by the genetic algorithm.It is found from the result that the validity of the algorithm is verified.In the fifth chapter,the main contents and innovations in this thesis are concluded,and several further research orientation are presented.