Modeling coupled mass and heat transfer in porous medium using finite element method

This dissertation describes a model of coupled mass and heat transfer in plane clothing fabrics which has improved the different models in this field dating back to the nineteenth century. A transient method for measuring the mass diffusivity in unsaturated clothing fabric, which is based on an analogy of mass diffusion, has been devised. An analytical equation which relates the mass diffusivity to the saturation in clothing fabrics has been derived using the Boltzmann transformation. A transient diffusion analogy model has been developed to simulate the plane (two dimensional) problems of water wicking movement and temperature distribution in clothing fabrics. A numerical model using both the transient, nonlinear finite element method (FEM) and the Artificial Modification Method (AMM) has been developed for predicting mass and heat transfer in plane clothing fabrics. Techniques for measuring both saturation and temperature in clothing fabrics have been devised. Experiments were conducted using a combination of polypropylene and cotton fabrics to create a two-dimensionally irregular wicking phenomena which could be used to test the theoretical calculations. These measurements verified that the current model can predict the wicking process in clothing fabrics very well.