Speaker
Description
Preferential flow in heterogeneous porous media leads to highly uneven transport and limits the efficiency of many natural and engineering processes. Although shear-thinning polymer solutions are widely used to modify flow behavior, their rheology often amplifies flow heterogeneity under strong permeability contrasts. Here we show that shear-thinning suspensions of cross-linked polymer particles exhibit a fundamentally different and counterintuitive behavior: they can actively homogenize flow through self-adaptive feedback between particle transport and local rheology. Using microfluidic experiments, direct numerical simulations, theoretical analysis and dynamic network modelling, we demonstrate that particle concentrations redistribute in response to local flow conditions, generating spatially varying viscosity through concentration-dependent rheology that suppresses the formation of preferential pathways. Unlike continuous polymer solutions, whose viscosity depends only on shear rate, the effective rheology of particle suspensions depends on the evolving particle concentration field, thereby reducing velocity contrasts across regions of different permeability. Using a pore-doublet model, we theoretically identify a three-dimensional regime space defined by particle concentration, channel-size ratio, and injection velocity that governs the emergence or suppression of preferential flow. These results are further upscaled to dual-permeability porous media using dynamic network modelling, revealing that homogenization is maximized at high particle concentrations and weakened at intermediate injection velocities and large permeability contrasts. These findings establish non-Newtonian particle suspensions as a self-adaptive strategy for controlling flow heterogeneity in porous media, with potential relevance to flow management in energy, environmental, and microfluidic applications involving strong structural heterogeneity.
| Country | China |
|---|---|
| Acceptance of the Terms & Conditions | Click here to agree |
