Numerical simulation of particle distribution characteristics and spatiotemporal disorder under the influence of various modified pitched blade turbine impellers

In the process of solid–liquid mixing, pitched blade turbine (PBT) is easy to cause a stable structure of particle flow, forming a pseudo-uniform state, and reducing the mixing efficiency. In this study, the morphology of PBT impeller was improved, and three new impellers were designed: cut diversion impeller 1 (CDI-1), cut diversion impeller 2 (CDI-2), and serrated impeller. The discrete element method–volume of fluid coupling method was used to numerically simulate the particle distribution and flow field structure characteristics under the action of the new impeller. An evaluation method of the average deviation range (DRav) was proposed to quantify the disorder of particle spatial and temporal distribution. The results show that the particle suspension ratio of the three new impellers is increased by 13.00%, 9.00%, and 18.00%, respectively, and the values of DRav are increased by 0.001, 0.0013, and 0.015 m, respectively, which effectively breaks the steady-state structure in the process of solid–liquid stirring.