INTERACTING LATTICE-GAS AUTOMATON STUDY OF LIQUID-GAS PROPERTIES IN POROUS-MEDIA

We describe how lattice-gas cellular automata may be used to simulate evaporation phenomena in models of porous media constructed at the por e scale. Two-dimensional simulations of evaporation are performed in s imple channel geometries and in a model of a microscopically disordere d porous medium. We describe a variant of the lattice gas, called the liquid-gas model. By static and dynamic tests we show that this model can simulate low Reynolds number mechanical and thermodynamical equati ons for isothermal evaporation in a real system made of a single-speci es liquid in equilibrium with its vapor. From static simulations in si mple geometries we obtain equilibrium pressures on both sides of a men iscus. These are seen to obey the Gibbs-Thomson relations, which are e quivalent to the Kelvin effect. We observe evaporation in simple capil lary channels and compare the results to a simple theory based on Pois euille flow. An unexpected effect is additional flow in the wetting fi lms and sharp density jumps. In simulations of evaporation in disorder ed geometries, we observe bursting and convoluted interfaces as previo usly reported in laboratory experiments.