DESIGN AND DEVELOPMENT OF HIGH SHEAR MIXER

Abstract

High shear mixers (HSMs), characterized by their highly localized energy dissipation, and are widely used in process industries for dispersed phase size reduction and reactive mixing. In order to create the highly localized energy dissipation a rotor stator assembly is required, also known as rotor-stator mixer (RSM). In this report various research articles on high shear mixers are reviewed. These include the application and uses of high shear mixers, their geometry, and their hydrodynamic characterization using computational fluid dynamic (CFD) techniques. Power draw is a characteristic parameter to describe the dynamic mixing state, which is fundamental to motor selection in the mixer design, optimization and scale-up. Therefore in the present work the CFD modeling of an existing HSM and a proposed novel HSM design is carried out using k-ε turbulence model. The results in both existing and proposed design are reported in terms of power draw, flow patterns and energy dissipation. The simulations were carried out using transient sliding mesh with k-ε turbulence model at a rotor speed of 4000 rpm for the validation with the existing results. The existing HSM is comprised of square holes in the stator and a rotor with 4 blades. The proposed mixer design is comprised of tilted jets/holes in the stator, for the deep penetration in the mixing vessel. For the optimization of operating as well as geometrical parameter of the proposed mixer design, the simulations are carried out at different rotor speeds. The mixing characterization of the square holes and proposed high shear mixer are also studied in this present work.