Speaker
Description
Clogging from particle-laden flows in confined porous environments spans multiple scales and is ubiquitous across biological, environmental, and engineered systems. It results from the obstruction of narrow pathways, causing permeability loss, reduced injectivity, and, in severe cases, complete blockage. Mitigation is therefore essential to sustain performance and extend the lifetime of porous media and filtration/injection operations. Conventional strategies rely on upstream filtration (sand/cartridge, microfiltration/ultrafiltration) or chemical dosing (chlorination, acidification), but they add infrastructure and/or require continuous treatment with ongoing costs and safety constraints. This motivates a passive hydrodynamic mitigation strategy based on pulsatile (oscillatory) flow, as an alternative to continuous injection. Prior studies suggest that pulsatile (oscillatory) operation can delay clogging relative to continuous flow, but most evidence comes from simplified channel arrays and often targets saline, adhesion-dominated regimes. Here, we examine externally imposed sinusoidal forcing at the pore scale in tortuous, rock-analog microfluidic porous networks across saline and non-saline conditions, enabling direct observation of particle transport, deposition, and clogging dynamics under oscillatory flow. Experiments are conducted under a pressure-driven protocol, and clogging is quantified from the normalized flow-rate decline. We apply a sinusoidally modulated pressure drop with a 100 mbar mean and a ±50 mbar amplitude at f = 0 Hz (continuous), 0.01 Hz, and 0.1 Hz, across three salinities (0, 1, and 100 mM). Under continuous injection, higher salinity accelerates the flow-rate decline as expected, indicating faster clogging in the heterogeneous porous medium. Replicates at each salinity are highly reproducible, providing a robust baseline to assess sinusoidal forcing. Particle image velocimetry (PIV) measures pore-scale velocities and confirms that the oscillatory forcing is transmitted throughout the pore space over the tested frequencies with no significant attenuation. At 1 and 100 mM, oscillatory forcing delays clogging and extends the time to complete blockage relative to the continuous baseline, with consistent trends across replicates. In non-saline conditions, the response is more frequency sensitive, with distinct clogging dynamics compared to continuous injection. This contrast may reflect a shift in the dominant pore-scale clogging mechanism, from interaction-controlled deposition at finite salinity to more hydrodynamic and geometry-controlled events under non-saline conditions. This mechanistic interpretation needs to be tested with additional pore-scale analysis. These findings highlight how oscillatory forcing can modulate clogging dynamics and extend pore-network lifetime before complete blockage, with practical implications for improving the performance and efficiency of porous systems.
| Country | France |
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