Diffusion in an absorbing porous medium : from microscopic geometry to macroscopic transport

Two physical models of diffusion in absorbing porous media are proposed on two length scales. One models diffusion in the pore space of a random medium with absorbing interfaces while the other is a reaction diffusion model where particles are absorbed in the bulk. Typical particle traveling distances and a bulk absorption coefficient are described in terms of general geometrical characteristics of a random medium and the analytical relations are found to compare well with numerical experiments. For the case of geometries consisting of randomly placed cubes, absorption in the bulk scales with the solid fraction to the two-thirds power. The statistical distribution of reaction rates in these models is found to be inversely related to the reaction rate. A quasi-static Monte-Carlo model is also investigated. The more complex problem of microbial extracellular enzyme distributions in marine sediment was an inspiration for this work.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Forney, David C., III

Advisor dc:contributor.advisor

• Daniel H. Rothman.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/40293

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/40293