چكيده به لاتين
The progress in numerical methods, computing equipment, and imaging techniques in the recent decades have led to an impressive improvement in modeling momentum, heat and mass transfer in porous media.The porous geometry details on the pore scale have a significant effect on the transport phenomena. Therefore, it is necessary to consider the geometric details or their effects in porous media simulations .However, it is generally not possible to simulate the whole problem on this scale. On the other hand, it is not possible to provide geometric details in the "macroscopic" simulations and the only way is to use the suitable transport coefficients to see the effects of geometric details in their final results. However, selecting the appropriate values for the coefficients is not always easy, and will be possible only with the knowledge of what is really happening in the pore scale.
In the present study, the mass transport phenomena in fibrous porous medium are simulated in the pore scale to calculate the effective diffusion coefficients for macro scale to simulation of methane catalytic combustion in this type of porous medium. The simulation were performed in generated fibrous porous medium. The geometry were recunstracted based on fibrous porous medium parameters. Using the simulation technique on the pore scale, the mass diffusion coefficient in fibrous porous media was calculated. The effect of the Solid Volume Fraction, fibers orientation and diameter were studied and it was shown that the SolidVolume Fraction has the most effect on these coefficients.Using the effective diffusion coefficients, and other coefficients of transfer phenomena for fiber porous media (Flow permeability, conduction heat transfer and radiant heat transfer) for a certain physics, the simulation of methane catalytic combustion was performed on a macro scale. The distribution of the obtained temperature and the reaction rate Were in good agreement with the measured data in previous studies.in this study had a 6.4% error in calculating the methane conversion rate.
