CFD Simulation of Solid Suspension in a Stirred Reactor Driven by a Dual Punched Rigid-Flexible Impeller

Abstract

Abstract Solid suspension characteristics were predicted by computational fluid dynamics (CFD) simulation in a stirred tank driven by a dual rigid-flexible impeller and a dual punched rigid-flexible impeller. An Eulerian-Eulerian approach, standard k-ε turbulence model, and multiple reference frames (MRF) technique were employed to simulate the solid-liquid two-phase flow, turbulent flow, and impeller rotation in the stirred tank, respectively. The CFD results showed that dual punched rigid-flexible impeller could increase the axial velocity and turbulent kinetic energy dissipation rate, and decrease the quantity of sediment solid particles compared with dual rigid-flexible impeller. Less impeller power was consumed by dual punched rigid-flexible impeller compared with dual rigid-flexible impeller at the same impeller speed. It was found that punched rigid-flexible impeller was more efficient in terms of solid suspension quality than dual rigid-flexible impeller at the same Pw. The simulated results for the axial solid concentration were in good agreement with the experimental data.