Analytical Solutions to Matrix Diffusion Problems

摘要

We report an analytical method to solve in a few cases of practical interest the equations which have traditionally been proposed for the matrix diffusion problem. In matrix diffusion, elements dissolved in ground water can penetrate the porous rock surronding the advective flow paths. In the context of radioactive waste repositories this phenomenon provides a mechenism by which the area of rock surface in contact with advecting elements is greatly enhaced, and can thus be an important delay mechanism. The cases solved are relevant for laborary as well for in situ experiments. Solutions are given as integral representations well suited for easy numerical solution.