摘要：
This dissertation consists of six chapters. The first one provides an introduction to the subject of this document. The next two examine and derive the mobile-immobile zone model for two different pores: a rectangular 2-D pore and an axisymmetric pore. The fourth chapter offers a numerical and laboratory experiments to study contaminant transport through a single pore. The fifth chapter focuses on whether or not fractional or Taylor dispersion controls the spread of solutes in porous media with significant presence of vortices. The final chapter studies the dynamic nature of the effective porosity. There also are three appendices. Below, each paragraph provides an abstract of 5 consecutive dissertation chapters, chapter 2 through 6. A new analytic solution has been derived for the diffusion into or from an immobile zone of a rectangular 2-D pore. This solution is expressed by a series of exponentials with the first term dominating all the other terms after relatively short dimensionless time of τ = Dt/a 2 > τo ≈ 0.15, where D is molecular diffusion, t is time, and a is the pore depth. Hence for long times, τ > τ o, the analytic solution converges to a single decaying exponential and takes the form of the mobile-immobile zone (MIM) model. However, the long-time solution differs from the traditional MIM model by having an apparent initial concentration smaller than the true one. The difference represents the MIM model error, which propagates in time. This error provides a relatively small price (below 19%) for using a much simpler model instead of the exact model based on the diffusion equation. For sufficiently long times, τ > τ o, the mass-transfer coefficient is practically constant, proportional to the molecular diffusion, and inversely proportional to the square of the pore depth. For sufficiently short times, τ < τo, the mass-transfer coefficient is time-dependent and may be significantly larger than its asymptotic value. New analytic and semi-analytic solutions
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