HR: 1330h
AN: H42F-1148    [PDF]
TI: Salt Precipitation and Dissolution in an Unsaturated Porous Media Under Non-Isothermal Conditions
AU: * Burns, E R
EM: burnse@engr.orst.edu
AF: Department of Bioengineering, Oregon State University 116 Gilmore Hall, Corvallis, OR 97331 United States
AU: Dragila, M I
EM: Maria.Dragila@oregonstate.edu
AF: Department of Crop and Soil Science, Oregon State University Agriculture & Life Science Building 3135, Corvallis, OR 97331 United States
AU: Weisbrod, N
EM: weisbrod@bgumail.bgu.ac.il
AF: Department of Environmental Hydrology & Microbiology Department of Environmental Hydrology & Microbiology Department of Environmental Hydrology & Microbiology, Institute for Water Sciences and Technologies Desert Research Institutes Ben-Gurion University of the Negev Sde-Boqer Campus, Sede Boqer, 84990 Israel AU: Guenther, R B
EM: guenth@math.orst.edu
AF: Department of Mathematics, Oregon State University Kidder Hall 368, Corvallis, OR 97331 United States
AU: Selker, J S
EM: selkerj@engr.orst.edu
AF: Department of Bioengineering, Oregon State University 116 Gilmore Hall, Corvallis, OR 97331 United States
AB: Salt precipitation and dissolution in unsaturated porous media is an important process to understand, both for agricultural soils (fertilizer movement) and for its effects in controlling water flux and potential contaminant transport in arid regions (migration of fluids and solutes to fractures and the land surface). Since evaporation is a key process to consider in both scenarios, it is necessary to consider heat and energy flow. A brief discussion/history of the salt precipitation/dissolution problem is given, then using the principles of continuum mechanics and mixture theory, a set of governing equations for salt precipitation and dissolution is developed. The equations are general in the sense that the following are considered: 1) non-isothermal conditions; 2) porosity is a function of solid phase salt concentration; 3) all parameters are functions of the appropriate thermodynamic variables. The equations are limited in that only near-ground surface conditions are considered. This is generally not a serious limitation since this location is likely the most seriously affected by rapid temporal changes in temperature and other boundary conditions. Further simplification of the problem is achieved by considering only "simple" salts (defined here as non-pH buffered salts that dissolve/precipitate only as a function of liquid phase ionic concentration) and flow regimes that do not result in finger flow of liquids. Initial and boundary conditions are developed for the following physically relevant conditions: 1) fertilizer salts introduced to an initially wet (but unsaturated) soil; 2) salt formation on free surfaces in arid climates; 3) water imbibition of fresh water into saline porous media. Work to date on solution of the initial boundary value problems is presented.
DE: 1866 Soil moisture
DE: 1875 Unsaturated zone
DE: 1878 Water/energy interactions
SC: Hydrology [H]
MN: 2003 Fall Meeting