Mathematical modelling and numerical simulation of moisture transfer in textile assemblies

Abstract

In this thesis, we study moisture transport in textile assemblies in a one dimensional setting. We formulate our problem using a multi-component flow model which covers heat/moisture convection, conduction, diffusion, phase change and water absorption in fibrous porous media. The model is based on a previous study with a significant modification to take into account the air resistance to moisture transfer. The results show that the convective velocity predicted by the new model is more realistic than the velocity given by the single component model. The capillary effect on liquid water motion which was negligible is also included in the model. In addition, the effective conductivity and capacity of the whole system are treated very carefully. The calculation for water content absorbed by fiber is separated from the governing equations, and therefore CPU time can be saved. An efficient semi-implicit numerical scheme is proposed for solving the gas, water content, and energy equations. The numerical results agree well with the main features of the experimental measurements. Further numerical simulations are done to show the thermal performance and water distribution of the porous media under different conditions.