Hydrodynamic Performance of a Ring‐Style High‐Shear Impeller in Newtonian and Shear‐Thinning Fluids

Laminar mixing of Newtonian and shear‐thinning fluids induced by a Hockmeyer®‐type impeller was investigated. Two unbaffled tanks at three impellers off‐bottom clearances (c) were studied. Six geometric combinations, i.e., two d/T and three c/T, were examined where d and T are the impeller and tank diameters, respectively. Determination of the Metzner‐Otto constant (Ks) was undertaken. The effects of d/T, c/T, and fluid rheology on Ks, power demand, pumping, shear and viscous dissipation were analyzed. The evaluated geometric ratios and rheology do not significantly affect Ks and power demand, only the rheology had an impact on the remaining hydrodynamic parameters. Pumping was favored with the Newtonian fluid, and shear and viscous dissipation increased with the shear‐thinning fluid. The hydrodynamic performance in the laminar regime of a ring‐style high‐shear impeller of two rings mixing Newtonian and shear‐thinning fluids was evaluated. The highest shear and viscous dissipation values induced by this impeller with the shear‐thinning fluids suggest that in the laminar regime these fluids exhibit a superior performance for powder dispersion processes than Newtonian fluids.