Simulation of Stresses Induced by Heat and Mass Transfer in Drying Process of Clay-like Material

Drying represents one of the oldest unit operations employed in industrial processes. Drying is viewed as a process of simultaneous heat and mass transfer. Porous Clay-like material undergoes stresses due to non-uniform distribution of temperature and moisture induced by heat and mass transfer respectively. The aim of this work is to simulate the stresses induced by heat and mass transfer during drying. A mathematical model to simulate the convective drying of a porous material like clay has been developed. The problem investigated involves highly coupled equations considering heat, mass, and mechanical aspects. The particularity of the model is that it takes into account the strong coupling between mass transport, heat transport and mechanical behavior of the material. The variables of coupling are the solid deformation, moisture content and temperature of porous medium. A numerical solution is sought to foresee the variation of moisture content, temperature, shrinkage, heat transfer induced stresses and mass transfer induced stresses during drying. The solution developed as a model is capable of predicting the quality of the product through a failure criterion. The model is validated through the comparison of simulated and experimental data. Simulation results show that the heat transfer induced stresses are 125E3 times higher than the mass transfer induced stresses and can be neglected in modeling of drying process.