The behavior of colloidal gels under pressure-driven flow in square microchannels is quantified by microscopic particle image velocimetry (μPTV) and compared to predictions of available rheological models. The gels consist of hydrophobically modified silica microspheres (Φ = 0.15-0.33) suspended in a refractive index-matched fluid along with fluorescent tracers to aid visualization. Measured velocity flow profiles show a transition from plug flow to more fluid-like behavior with increasing volumetric flow rate (Q) at all Φ. This transition is not captured by theoretical predictions of the flow profile based on the Herschel-Bulkley model. Rather, a model that accounts for gel breakup into a suspension of clusters at elevated shear rates by assuming a finite viscosity at infinite shear is needed to accurately predict the flow behavior of colloidal gels at large Q.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Aug 14 2007|
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics
- Surfaces and Interfaces