HR: 1340h
AN: H53E-1462    [Abstracts]
TI: Measurement of Thin Film Characteristics in Porous Media
AU: * Thornley, E
EM: thornlee@onid.orst.edu
AF: Department of Chemical, Biological and Environmental Engineering Oregon State University, 102 Gleeson Hall, Corvallis, OR 97330,
AU: Jansik, D
EM: jansikd@onid.orst.edu
AF: Department of Chemical, Biological and Environmental Engineering Oregon State University, 102 Gleeson Hall, Corvallis, OR 97330,
AU: Wildenschild, D
EM: dorthe@engr.orst.edu
AF: Department of Chemical, Biological and Environmental Engineering Oregon State University, 102 Gleeson Hall, Corvallis, OR 97330,
AB: Liquid film formation in unsaturated subsurface porous media is commonly not accounted for in flow and transport models. Characteristics of this type of film flow are complex to quantify and are therefore often overlooked, despite the apparent need for a more complete low saturation flow model in fields such as hazardous waste disposal, enhanced oil recovery, and environmental contamination situations. The most important effects of film flow in porous media relate to available interfacial areas, meniscus curvature development, and permeability; greater understanding of these effects is necessary to accurately model these low saturation flow situations. In order to examine this topic further, we have created two-dimensional, pore scale flow cells containing crushed Yucca Mountain tuff. Tuff is characterized by large surface areas and intra-granular porosity which encourages thin film formation. Using these flow cells, relative humidity sensors, and a digital microscope and image processing software, the saturation and capillary pressure (as relative humidity) inside of the cells are measured. The measured values allow us to estimate the saturation point at which Van der Waals forces no longer dominate and capillary forces become the controlling factor. This point is characterized by the formation of pendular rings from condensing thin films. By introducing water into the cell and subsequently drying it, the formation of thin films and pendular rings can be observed while relative humidity and temperature are recorded. Relative humidity and temperature are then related to capillary pressure and saturation using the Kelvin and Young-LaPlace equations. Using this data and imaging analysis, the transition point from pendular rings to film- dominated flow can be related to the saturations and capillary pressures.
DE: 1859 Rocks: physical properties
DE: 1866 Soil moisture
DE: 1875 Vadose zone
DE: 3947 Surfaces and interfaces
SC: Hydrology [H]
MN: 2007 Fall Meeting