Survival probability in the transition and Knudsen diffusion regime in random fiberstructures

摘要

Computer simulation results are presented for the molecular survival probability in the transition andKnudsen diffusion regime, in random porous media formed by cylindrical fibers randomly distributed inthe three-dimensional space. The numerical procedure is based on a discrete random walk mechanismsimulating the molecular trajectories for various values of the porosity and Knudsen number. Thesurvival probability is found to increase with the porosity in both the transition and Knudsen regime. Itsvalues in the transition regime depend strongly on the Knudsen number, whereas in the Knudsen regimethey are in line with analytical predictions based on the chord length distribution of the fiber structures.