On pore scale modelling of mechanical dispersion

This paper reports on an investigation of pore-scale modelling for closure of a volume averaged equation with goal the quantitative prediction of a dispersion coefficient for mechanical tracer transport in isotropic porous media. In fluid motion through porous media the molecular diffusion can sometimes be neglected leaving the convective distribution of the tracer concentration the prime contribution to dispersion. Volume averaging of the particular tracer transport equation is discussed. A representative unit cell model is then used to obtain residence times from which some measure of the dispersion coefficient is obtainable. Conclusions about the feasibility of the method has yet to be attained but the exercise has proved instructive in understanding the underlying physical principles.