Experimental Study And Numerical Simulation Of Macromixing & Micromixing In Stirred Tanks

Agitated reactors/tanks are widely used in many industrial processes. The performances of macromixing and micromixing are of importance to the optimal design of stirred reactor, especially when involved fast complex reactions. In this paper, macromixing and micromixing were studied by experimental approach and using numerical simulations.The mixing time experiments were carried out in a perspex vessel of 0.476m in diameter. The mixing time was measured by using a conductivity probe. Single and multiple standard Rushton disc turbine (DT-6), 3-narrow-blade hydrofoil CBY impeller were used in the experiments to investigate the effect of agitator type on the mixing time.The mixing time in the stirred tank was numerically simulated by using computational fluid dynamics (CFD) package FLUENT6.1 on a PC cluster. Reynolds-averaged Navier-Stokes (RANS) approach with multi-reference frame (MRF) and standard k-ε turbulent model was used in the simulation in the first stage. The momentum and mass equations were computed separately. The mixing time predicted by CFD for the single DT-6, CBY impeller and multiple CBY impellers was in good agreement with the experiment. The mixing time predicted by CFD for the dual DT-6 impellers was about twice experimental. The effects of tracer feeding and detecting...