Optimization strategies of impeller blades for effective mixing of solid–liquid two‐phase in a stirred tank reactor

Abstract

In this work, the solid suspension characteristics in the stirred tank with a fractal arrangement cut impeller (FAC impeller) were investigated by experimental techniques and numerical simulations. The results presented that FAC impeller featured the lower power consumption and power number, and shorter mixing time compared with the traditional pitched blade turbine (PBT), and these phenomena become increasingly pronounced with the iteration count of cuts in the impeller blades grew. Specifically, the power number for FAC‐1 impeller and FAC‐2 impeller systems were observed to be approximately 13.2% and 20.8% lower than that of PBT system, and the mixing time for FAC‐1 impeller and FAC‐2 impeller systems were found to be approximately 5.82%–19.3% and 15.5%–32.7% lower than that of PBT system. Moreover, fractal arrangement cut design for the impeller blades could increase the K entropy, improve the solid axial velocity, turbulent kinetic energy, and turbulent kinetic energy dissipation rate, reduce the accumulation of solid particles at the tank bottom, enhance the uniformity of local axial solid holdup and the solid suspension quality, and simultaneously decrease the critical suspension speed compared with the conventional designs.