Viscosimetric squeeze flow of suspensions

Area of Science:

• Fluid Dynamics
• Materials Science
• Rheology

Background:

• Particle suspension rheology is well-studied in simple shear flow.
• Other flow configurations, like squeeze flow, are practically relevant but less explored.
• Understanding suspension behavior in diverse flows is crucial for industrial applications.

Purpose of the Study:

• To investigate the rheology of particle suspensions in a squeeze flow configuration.
• To utilize local pressure measurements for deducing effective viscosity.
• To validate the applicability of established rheological laws in squeeze flow.

Main Methods:

• Generating squeeze flow using a moving disk approaching a fixed wall at low Reynolds number.
• Measuring the evolution of the pressure field at the wall.
• Deducing effective viscosity from the radial pressure drop.
• Validating the experimental setup with a Newtonian fluid.

Main Results:

• Effective viscosity of particle suspensions was measured for varying squeezing speeds and particle volume fractions.
• Experimental results demonstrated agreement with the Maron-Pierce law, typically observed in simple shear flows.
• The method for viscosity determination was validated for large gap widths.

Conclusions:

• Squeeze flow rheology measurements using local pressure are effective for characterizing particle suspensions.
• The Maron-Pierce law is applicable to particle suspensions in squeeze flow.
• This technique enables the study of large-particle suspensions in large gaps, overcoming limitations of traditional methods like Couette flow cells.