Redefining the shear rheology of concentrated suspensions


Project Leader: Anthony Stickland
Staff: Anthony Stickland, Peter Scales
Collaborators: Richard Buscall (MSACT consulting)
Primary Contact: Anthony Stickland (stad@unimelb.edu.au)
Keywords: separation processes
Disciplines: Chemical & Biomolecular Engineering
Domains: Convergence of engineering and IT with the life sciences
Research Centre: Particulate Fluids Processing Centre (PFPC)

Understanding the flow and deformation, or rheology, of suspensions is important for many processes and products. Suspension shear rheology is typically described using models with a yield stress such as the Bingham model or extensions thereof like Herschel-Bulkley.  Such models are tolerably capable of predicting gross features like pressure drop in pipe flow and overall flow rate but they cannot be relied upon to predict flow-fields since many suspensions do not flow like simple liquids once they yield; many show phenomena such as time-dependent yield, localisation and shear-banding.  It is hypothesised that the sharp transition behaviour can be described not as plastic yielding but in terms of non-linear viscoelastic energy conservation and dissipation strain and/or strain-rate functions. This approach accounts for such phenomena without requiring exotic explanations such as thixotropy for example. This project will develop experimental techniques, analysis methods and rheological models that implement the viscoelastic approach. This includes providing a fingerprinting type approach to define classes of suspension behaviour based on the linear to non-linear viscoelastic transition.