Escape of a rarefied gas into vacuum through a nonhomogeneous porous layer

Mass transfer in filtration or evaporation of a substance from a deepened surface in a highly porous layer and in escape into vacuum is calculated based on the Monte Carlo method. It is assumed that the porous layer contains individual inclusions in which the porosity is a random quantity. Account is taken of the possibility of the gas molecules being absorbed on the surface of the particles of the porous body. The angular distributions of molecules emerging from the layer are obtained. The nonmonotonic character of the distribution of the molecules absorbed which is caused by the presence of the inclusions is revealed.