Towards Advanced in Situ Measurements of Complex Rheological Properties in Manufacturing Processes - identification of a "finger print" of a fluid

New Product Developments (NPD) is an ongoing activity involving frequent new and improved products being transferred from laboratory scale development to manufacturing at "tonne scale". Traditional approaches to NPD focus the attention at laboratory scale with little or no attention to a formulation's "manufacturability". These issues are typically only addressed during scale up, at pilot scale and are often not fully resolved when the product goes to manufacturing scale. Such an approach to scale up also involves compromises. These result in not only longer and costlier scale up but also frequently increased production costs. These critical challenges also limit industry's ability to achieve more efficient and flexible processes. A way to deal with these challenges with a different approach is to improve the capabilities in terms of in situ measurements. Complex rheological characterisation is one of the most desired measurement in industry, being most of micro and macro structure of formulated products strongly related to their rheological properties. Currently, there are limited options available in the market shelf. The desired specifics, for such measurement tool, are the possibility of real time and non-intrusive measurements. The characterisation of complex rheology must not be confused with a simple viscosity measurement. In fact, most of the online or in situ rheological measurement available in the market can only describe the viscosity of a fluid at fix shear rate (viscometer). As it is well known, most of complex rheology presents a non-linear relationship between the shear rate and the shear stress. This is why viscometer measurements cannot be reliable for the characterisation of complex fluid rheology. Much more reliable, off line measurements, such cone and plate rheometer, are used to acquire a detailed flow ramp (shear Rate vs shear Stress curve). However, the drawbacks are time scale of measurement (~10 minutes) which is far from the desired one (~1 s) and being off line.
The project aims to fulfil the gap that exists in the literature trying to understand more deeply the link between fluid flow and complex rheology. The challenge is to determine the "finger print" of a fluid rheology from its developed flow features achieved flowing in designed obstructions. The first objective is to link rheology properties to flow properties; understanding flow development from steady pipe flow to perturbed flow due to obstacles and this will be mainly done using PIV (Particle Image Velocimetry). Secondly, understanding the effect of adding a peristaltic flow to the system and verifying its effect on fluid flow developments. The other part of the project is to link all information to models using statistical or analytical approach.