Infinite Shear Viscosity Research Articles

Flow behaviour of oil‐in‐water emulsions

AbstractThe rheological behaviour of concentrated oil‐in‐water emulsions has been investigated using the Weissenberg Rheogoniometer. The oil concentration has been varied from 40 to 95 volume percent. The effects of shear rate and oil concentration on the viscosity have been determined. From the rheological data, the maximum attainable oil concentration in the emulsion has been estimated and is introduced as a parameter in the relationship between relative viscosity and oil concentration to account for certain variations in the emulsion characteristics. Empirical equations have been obtained which correlate zero shear rate viscosity and infinite shear viscosity as a function of reduced oil concentration. Comparison has been made between the emulsion viscosity and the solid‐liquid suspension viscosity at high dispersed phase concentration. Estimated maximum attainable oil concentration is found to be in close agreement with the actual maximum concentration that could be achieved experimentally.

A three-parameter model describing the experimental relation between shear stress and shear rate for laminar flow of aqueous polymer solutions

A three-parameter model is introduced to describe the shear rate — shear stress relation for dilute aqueous solutions of polyacrylamide (Separan AP-30) or polyethylenoxide (Polyox WSR-301) in the concentration range 50 wppm − 10,000 wppm. Solutions of both polymers show for\(1000 s^{ - 1}< \dot \gamma< 50,000 s^{ - 1} \) a similar rheological behaviour. This behaviour can be described by an equation having three parameters i.e. “zero-shear viscosity”η0, “infinite-shear viscosity”η∞, and “yield stress”τ0, each depending on the polymer concentration. A good agreement is found between the values calculated with this three-parameter model and the experimental results obtained with a cone-and-plate rheogoniometer and those determined with a capillary-tube rheometer.