Flowing Polymers Through Porous Media: An Experimental Study of Flow Distribution, Polymer Degradation, and Molecular Weight Effects

The flow of aqueous poly(ethylene oxide) solutions through nonconsolidated porous media has been experimentally investigated. Three aspects of practical relevance have been addressed: the effect of polymer on flow distribution under nonuniform flow conditions, the mechanical degradation of the polymer in the porous media, and the effect of molecular weight on flow resistance. The nonuniform flow results indicate that, although the presence of polymer changes the distribution of the flow by affecting the region of the medium that is swept by the fluid, a significant increase in flow resistance is still observed above a critical Reynolds number, as it happens under uniform flow conditions. The degradation experiments show that the polymer is significantly degraded only in the region where a sizable increase in flow resistance is obtained with respect to the Newtonian behavior. The most significant effect of the molecular weight of the polymer is the fact that an increase in that parameter results in a substantial reduction of the Reynolds number at which the increased flow resistance is observed. Furthermore, the rate of change of this onset Reynolds number with polymer concentration appears to be independent of molecular weight. The results presented here indicate that the increase in flow resistance is not exclusively determined by the shear viscosity of the polymer solution.