Particle deposition in porous media: Analysis of hydrodynamic and weak inertial effects

We have studied the transport and capture of non-Brownian particles in poro us media, when the particles are mainly submitted to hydrodynamic and weak inertial effects. Visualization experiments have been performed using sever al models of porous media which consist of transparent etched networks of i nterconnected channels. Typical particle deposits have been observed at the corners of the grains of the porous medium. Their shape and their orientat ion were dependent on flow rate and on the anisotropy of the flow field. A trajectory analysis model has been applied to a porous medium made of a dou bly periodic array of rectangular grains very close to the experimental mod el. This numerical model has been used to localize particle deposits and to determine particle capture efficiency on the grains over a range of low St okes numbers, grain aspect ratios and flow-field anisotropy ratios. The res ults have been interpreted in terms of shape of particle deposits and compa red successfully to experimental observations.