ABSTRACT
Two sets of nonlinear coupled heat and mass transfer models are presented to describe the absorption and desorption process. The solutions to the systems of equations were obtained by the finite element method.
Model one describes 280the temperature and moisture distribution in a general two phase system with a moving evaporation front. The interface condition at the evaporation front takes into account the moisture transfer balance at the moving boundary. The effect of the nondimensional heat of vapourization parameter on the evaporation front, temperature, and moisture distribution was studied. The movement of the evaporation front had an appreciable effect on
the temperature and moisture distribution inside the porous media. The temperature decreased and the moisture content increased as the nondimensional vapourization parameter increased. This model has potential applications in studying the heat and mass transfer characteristics in food and biomaterials.
Model two describes the coupled heat, mass, and pressure transfer in a porous material. The model was applied to simulate the temperature, moisture, and pressure distribution in a barley kernel during steeping. Simulated results indicated that a pressure gradient exists during the transfer process, causing additional moisture movement due to filtration effect. This technique can be used for determining optimum soaking time required for soaking the kernels with steep water. The discussion contains two parts: Application I and Application II dealing with the desorption and adsorption process respectively.
