NUMERICAL EXPERIMENTS ON PAPER-FLUID INTERACTION - PERMEABILITY OF A 3-DIMENSIONAL ANISOTROPIC FIBER NETWORK

The effect of paper structure on flow characteristics of various fluid s is one of the most important, fundamental problems in papermaking, c oating, and printing. A computer code based on a cellular automaton mo del, in particular the lattice-gas Boltzmann model, has been developed to simulate flow numerically in a random fibre network. As a prelimin ary investigation, a numerical experiment has been conducted on the th ree-dimensional permeability of an interpenetrable fibre network. It w as found that the in-plane permeability and the z-directional (thickne ss direction) permeability are very sensitive to the distribution of f ibre segments in the z-direction. At a constant porosity, the z-direct ional permeability increases and the in-plane permeability decreases w ith increasing z-directional fibre orientation.