Influence of porosity and direction of flow on tortuosity in unconsolidated porous media
Tortuosity {tau} is defined as the square of the ratio, {phi}-range of the effective length of pore channels to the length parallel to the overall direction of the pore channels in a porous medium. It has significance in interpreting the hydraulic and electric properties of porous media. In this study, experimental results of tortuosity and porosity {phi} were investigated in relation to different directions of flow in various unconsolidated porous media. When the media (mica, textile fibers, kaolinite, and bituminous soil, with a high {phi}-range of {approx}60--90%) are exposed to flow perpendicular to the planes and fibers, {tau} responds positively to {phi}. When the media (randomly packed beds of spheres, with a medium {phi}-range of {approx}34--45%) are exposed to flow parallel to the planes, {tau} responds negatively to {phi}. When the media (glass powders, glass spheres, dry soil, quartz sand, and white sand, with a variety of grain sizes and a medium porosity {phi}-range of {approx}37--47%), and other media (glass spheres, with different fractions of grain sizes and a low {phi}-range of {approx}10--30%) are exposed to nondirectional flow, {tau} responds negatively to {phi}. Empirical equations linking {tau} and {phi}, with medium to high coefficients of correlation, were obtained. The dependence of {tau} on {phi} is governed greatly by the direction of flow because of the orientation, mineralogy, and mode of packing of the grains and nonuniformity in the size and shape of the grains and pores.
- Research Organization:
- Atlantic Geo-Technology, Halifax, Nova Scotia (CA)
- OSTI ID:
- 20020917
- Journal Information:
- Energy Sources, Vol. 22, Issue 3; Other Information: PBD: Apr 2000; ISSN 0090-8312
- Country of Publication:
- United States
- Language:
- English
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