Stress-blended eddy simulation of flow characteristics in stirred tanks with different curved blade impellers

Abstract

A high-performance impeller is crucial for enhancing material mixing in a stirred tank. In this work, the flow characteristics created by different curved blade impellers including staggered fan-shaped parabolic disc turbine (SFPDT), swept-back parabolic disc turbine (SPDT), asymmetric staggered parabolic disc turbine (ASPDT) and traditional parabolic disc turbine (PDT) in stirred tanks are investigated numerically by using the stress-blended eddy simulation (SBES) model with a sliding mesh approach. After successful validation of prediction accuracy, power characteristics, mean flow, turbulence characteristics, turbulent kinetic energy (TKE) transport, and trailing vortices behaviors of SFPDT, ASPDT, SPDT and PDT in stirred tanks are systematically evaluated. The results show that ASPDT leads to a significant asymmetric distribution in the axial direction for velocity, TKE and trailing vortices, but the radial jet reduces more severely in the radial direction. The fan-shaped geometry constrains the influence of asymmetric staggered structure on the TKE and trailing vortices distribution for SFPDT. The swept-back blade structure of SPDT results in the lowest power number and TKE values level. These results provide a foundation for the further development and application of high-efficiency impellers.