Measurements of dispersion coefficients in porous media by pulsed field gradient NMR
نویسندگان
چکیده
Dispersion in porous media is currently an important subject that occurs in different domains (processes, environment, oil recovery...). We have used the nuclear magnetic resonance, and more precisely the Pulsed Field Gradient (PFG-NMR) techniques to characterize this phenomenon. A PGSTE sequence (Pulsed Field Gradient Stimulated Echo) is used to measure longitudinal and transversal displacements of water in packed beds of PMMA beads 75-90 μm in diameter. In unsteady state, the propagator formalism is used to measure average velocity and also longitudinal and transversal dispersion coefficients. Mots clefs : coefficient de dispersion, milieux poreux, propagateur de diffusion, RMN,
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