Dispersion and transport of gas-phase contaminants in dry porous media: effect of heterogeneity and gas velocity

摘要

The purpose of these experiments was to study the effects of physical heterogeneity and velocity on transport of gas-phase contaminants in dry porous media. Experiments were conducted at gas velocities ranging from 6 to 200cm min~(-1) to examine the contributions of longitudinal molecular diffusion, hydrodynamic dispersion, and rate-limited diffusive mass transfer to solute spreading. Methane was used as a nonreactive tracer, and trichloroethene, benzene and toluene were used as reactive tracers. Total dispersion of methane during transport through a homoge- neous porous medium was the sum of longitudinal molecular diffusion and hydrodynamic dispersion.