Specific features of power characteristics of in-line rotor–stator mixers

• High-shear rotor–stator mixers generate locally very high shear stresses due to focused delivery of energy.
• Only energy dissipated in high shear regions is effective for drop dispersion, which defines problem of efficiency.
• New expression for power draw helps to characterize dissipation of energy in different regions of rotor–stator.
• It is validated using experimental data and CFD simulation and used to define efficiency of drop breakage.
• It is used together with the multifractal model of turbulence to explain scale-up rules for drop dispersion.

Methodthat can be used to predict agitation power of in-line rotor–stator mixers are considered in this paper. Results of experimental investigations of power draw are presented and interpreted by using proposed phenomenological models and CFD predictions for the Silverson rotor–stator 150/250 MS device and its modifications. Results of theoretical analysis lead to extended version of previously used correlation for the agitation power. Based on new correlation and the multifractal model of turbulence the problems of energetic efficiency and scale-up of drop breakage in the rotor–stator devices are presented and discussed.