Modelling and Simulation of 2D-flow Suspension Diffusioosmosis
Résumé
Diffusioosmosis, also referred to as capillary osmosis, is the flow of a solution relative to a fixed object, where the flow is driven by solute concentration gradient. The solution considered here is an aqueous mixture containing colloids that flows in a channel and through an array of cylinders, representing a membrane. In this work we use an adaptation of the suspension balance model to investigate the influence of colloid-interface (Π ic) interaction and colloid-colloid interactions (Π cc) on the diffusioosmosis of a colloidal suspension. The model describes both osmosis and Marangoni flow, depending on the attractive or repulsive nature of Π ic. Further, Π cc dictates two important features of the flow. First, increasing the gradient of colloid concentration between the two channels by a factor of 10 increases the pressure drop by a factor of ~3.2 in the advectionosmosis equilibrium state. Second, including higher-order terms from the hard-sphere repulsion model (via the Carnahan-Starling equation of state) can increase colloid concentrations near the membrane by ~30%.
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