Particle Motions in Non‐Newtonian Media. II. Poiseuille Flow

The behavior of rigid and deformable particles suspended in pseudoplastic and elasticoviscous liquids undergoing tube flow was studied. The velocity profiles were more blunted than those obtained for Newtonian fluids and, as in Couette flow, the measured angular velocities of rigid spheres, rods, and discs were in accord with the theory for Newtonian liquids. There was also a drift in the orbit of the cylinders to limiting values corresponding to minimum energy dissipation in the flow. In elasticoviscous liquids, rigid particles migrated across the planes of shear towards the tube axis whereas in pseudoplastic liquids, the opposite was observed, rigid spheres actually coming in contact with the wall. The lateral migration of deformed liquid drops in elasticoviscous fluids was, as in Newtonian systems, towards the tube axis whereas in pseudoplastic liquids the drops attained an equilibrium position between the tube wall and axis. An accumulation of rigid spheres behind an advancing suspension‐air meniscus ...