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Transport and deposition of suspended particles in saturated porous media: hydrodynamic effect 总被引：1，自引：1，他引：1
Nasre-Dine Ahfir Hua Qing Wang Ahmed Benamar Adbellah Alem Nicolas Massei Jean-Paul Dupont 《Hydrogeology Journal》2007,15(4):659-668
A laboratory study was undertaken to determine the transport and deposition rate of suspended particles in columns of saturated porous media (gravel and glass beads), where the porous media were subjected to steady-state flow. Silt particles with a mode of 14 μm diameter (used as the suspended particles) and fluorescein (as the conservative tracer) were injected into the columns in short pulses. The breakthrough curves were competently described with the analytical solution of a convection–dispersion equation with a first-order deposition rate. The experiments were performed using different flow rates. The suspended particle size distribution, the porous media, and the flow rates themselves were the main factors retained in this study to investigate the mechanisms governing the transport and deposition kinetics in detail. The results showed the existence of a flow rate, beyond which suspended particles travel faster than the conservative tracer. A decrease of the deposition rate of suspended particles beyond a critical flow velocity was also observed. Such behaviour led to consideration of the couple hydrodynamic-gravity forces at high flow rates. As the hydrodynamic force increases, particle deposition rates are reduced due to the effect of hydrodynamic forces inhibiting the deposition. 相似文献
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Tahar Ikni Ahmed Benamar Mohamed Kadri Nasre-Dine Ahfir Hua-Qing Wang 《Comptes Rendus Geoscience》2013,345(9-10):392-400
The transport and filtration behaviour of fine particles (silt) in columns packed with sand was investigated under saturated conditions by using step-input injections. Three samples of different particle size distributions (coarse medium, fine medium and a mixture of both) were used in order to highlight the influence of the pore size distribution on particle retention and size selection of recovered particles. The main parameters of particle transport and deposition were derived from the adjustment of the experimental breakthrough curves by an analytical model. The higher particle retention occurs in the mixture medium, owing to its large pore size distribution, and the filtration coefficient decreases with increasing flow velocity. Particle size distribution of recovered particles shows a thorough size selection: (i) the first recovered particles are the coarser ones; (ii) the size of the recovered particles increases with increasing flow velocity and enlarger pore distribution of the medium. 相似文献
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Ahmed Benamar HuaQing Wang Nasre-dine Ahfir Abdellah Alem Nicolas Masséi Jean-Paul Dupont 《Comptes Rendus Geoscience》2005,337(5):497-504
We study in this paper the transport and deposition of suspended particles in saturated porous media. Some chromatographic short-pulse tests were performed in a laboratory column with a tracer and two types of suspended particles. A mathematical model was used to determine the hydrodispersive parameters and deposition rates from the breakthrough curves. The results show that the fitted parameters obtained vary with the flow rate and the characteristics of the suspended particles. We also observe, at high flow rates, that particles have a migration velocity higher than that of the conservative tracer. To cite this article: A. Benamar et al., C. R. Geoscience 337 (2005). 相似文献
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Abdellah Alem Abdulghadir Elkawafi Nasre-Dine Ahfir HuaQing Wang 《Hydrogeology Journal》2013,21(3):573-586
A study was undertaken on physical clogging of a porous medium by injecting suspended particles (SP), ranging in diameter from 1.7 to 40 μm, into a sand-filled column. Long-term tracer tests were carried out at various flow velocities. Retention of the SP is significantly influenced by the flow velocity. At low flow velocities, retention is confined to a limited length of porous medium, from the entrance of the column, leading to a substantial modification of the hydraulic characteristics of the porous medium. However, at high flow velocities, a much greater length of the porous medium is affected. Particle-size analyses indicate that the particle-size distribution (PSD) of recovered particles changes with time, while the PSD of retained particles changes with depth and time. At the beginning of the filtration process, larger particles were mainly retained at the column entrance. As the injection volume increases, the larger particles penetrate more deeply into the porous medium, and the size of particles observed in the effluent gradually increases. This study highlights the influence of flow velocity, duration of filtration, and the particles’ polydispersity, on the hydraulic characteristics of the porous medium. 相似文献
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