The Drying Characteristics Of The Couple Heat And Mass Transfer In Porous Material Based On The Theory Of Apparent Warp Activation Energy

The drying process is a complex heat physics process which is broadly applied in the production of industry,agriculture and in the human's living. Heat and mass transfer are simultaneous in the porous media. Many study results in the subject have been made for the last tens years. However, the experiment is still primary study means for the process of porous media's drying was complicated, changeful, non-steady. Therefore, it had important theoretical meaning and practical value for organizing the drying process in reason, reducing energy consumption and advancing the drying product's quality that the heat and mass transfer's theory of drying should be enriched and perfected and the cognition of the physical mechanism of the porous media's drying should be enhanced.Based on warp apparent activation energy theory and non-equilibrium thermodynamic theory, the law of energy and mass conservation, and the second law of thermodynamics, a mathematical model for convective drying of porous media was established and the numerical calculation was performed. Primary mechanisms of transportation for liquid and gas in drying process of porous media were analyzed. Capillary transportation of liquid and diffusive transportation were considerer else. The coupled heat and mass transfer phenomena were considered enough in this model. The simulated results were compared with experimental data and the variation of the porous materials` moisture content can be predicted.An experimental system had been established to validate the precision of dynamic mathematical model. The slab-shaped was used in the study. Temperature and averaging moisture content within the porous media were measured during drying. Comparison between experimental findings and numerical results shows a good coherence, which proves the model reasonable. Moreover, distributions of drying state-variable and warp apparent activation energy were simulated with numerical technique, and intrinsic causes were discussed. It can be concluded that the influence of heat on mass transfer can't be neglected, on the contrary, the influence of mass transfer on heat on heat can be neglected.The results indicated that it was a useful approach for the industrial to study drying and investigate the dynamical characteristics of materials to be dried by the way of the warp apparent activation energy theory. This job provided a foundation for further researching drying characteristics of industrial products. This provided the theoretical and technological basis for study on drying dynamic of the optimization of drying program.