Granular Flow Modeling combines the inherent frictional nature of particles with its distinctly fluid-like structure. We focus on two classes of flows:
(i) Free surface flows and (ii) Confined flows. Tumbling mills, chutes and avalanches are examples of Free Surface flows while Cyclonic Separators and Stirred Mills fall into the class of confined flows. Given the high concentration of solids in industrial flows, the granular flow approximation is unique in its ability to capture the solid-solid interactions within a continuum framework, typical of fluid flow. The physically valid dissipative mechanisms associated with granular material allows for more realistic quantification of abrasion and attrition in comminution processes while accurately capturing important flow features like free surface shape and velocity field profiles.
Industrial systems such as tumbling mills (see animation) are typified by rotational and axial flows of rock, steel balls and slurry. The tortuous, porous network created by the non-uniform packing of rock and steel balls form the channels through which the viscous slurry flows. A multi-pronged approach employing non-invasive nuclear techniques (PEPT, X-ray) and computational modelling (DEM, CFD, SPH) form the key ingredients for mechanistic modelling of such industrial systems.
Biological processes such as breathing are characterised by non-linear deformation of the tissue and musculature in the human upper airway. PEPT and X-ray imaging are employed to elucidate the mechanisms responsible for conditions such as Obstructive sleep apnea (OSA) where gross deformations (and subsequent collapse) of the pharyngeal airway cause prolonged pauses in breathing during sleep. The associated airflow that provide the stimulus for the final deformation is also tracked experimentally using PEPT. These measurements compliment coupled FEM-FCD modelling of the upper airway.
The PEPT and X-ray imaging techniques constitute the core measurement tools of the Particle Technology Group for understanding complex particulate and deformable systems. The resulting measurements inform our choices in the development of suitable granular flow models.
