Bidisperse particle-laden thin-film models and experiments

In our lab, we study particle-laden flow in viscous thin films driven by gravity. We model the fluid flow using a continuum approach for the particles that incorporates the Navier-Stokes equations and conservation of the particle volume fraction equations. This talk focuses on the effects of negatively buoyant particles in thin-film flow, specifically when the particles are of two different sizes. We present experimental observations of particles settling in a column and explore their implications for our theoretical models of diffusive flux. These observations are considered within the context of bidisperse flows on an incline and in a spiral geometry. We will present similar models for these two geometries, with particular attention to how the particle-fluid mixture equilibrates in a cross-section of a spiral separator. The main motivation for this research is to better understand the separation processes in materials, such as those used in the mining industry. Our theoretical framework aims to provide insights that could inform the design and optimization of spiral separators.