CFD simulation and experimental analysis of solid-liquid mixing characteristics in a stirred tank with a self-similarity impeller

Background: The nonlinear geometry could create a longer turbulence production region and higher turbulence intensities compared with conventional geometry. A self-similarity impeller based on Hibert curves was introduced to intensify the solid-liquid chaotic mixing process in this work.Methods: The hydrodynamics of solid-liquid mixing process in a stirred tank with pitched-blade impeller, selfsimilarity 1 impeller and self-similarity 2 impeller were studied through experimental analyses and numerical simulation.Significant findings: Results showed that self-similarity impeller could consume less power consumption compared with pitched-blade impeller at the same impeller speed. Self-similarity impeller could improve the largest Lyapunov exponent (LLE) value compared with pitched-blade impeller under the constant power consumption, and the LLE value continued to increase with the increase of the number of self-similar iterations. Meanwhile, selfsimilarity impeller could improve the solid particle suspension quality compared with pitched-blade impeller under the constant power consumption, and increasingly so with the self-similar iteration number. Moreover, self-similarity impeller could destroy the large tailing vortex and recirculation zone, and enhance the turbulent kinetic energy dissipation rate by the jet flows through the concave-convex edges compared with pitched-blade impeller, and this phenomenon became obvious with the increase of self-similar iteration number.

Automated summary

In this study, a self-similarity impeller based on Hibert curves was introduced to intensify the solid-liquid chaotic mixing process. The hydrodynamics of solid-liquid mixing process in a stirred tank with different impellers were investigated through experimental analyses and numerical simulation. The results showed that the self-similarity impeller consumed less power compared with the conventional pitched-blade impeller, improved the largest Lyapunov exponent (LLE) value, and enhanced the solid particle suspension quality and turbulent kinetic energy dissipation rate.