Hydrodynamics of batch stirred tank having multiple impellers: experimental and CFD study

Stirred tank is the most commonly used equipment for homogenous and heterogeneous mixing required for various unit operations and reaction's. Some of the applications in nuclear fuel cycle are leaching of uranium from its ore and precipitation of ammonium diuranate. Processing at higher capacity requires larger tanks and in such tanks a single impeller cannot provide adequate mixing. This necessitates use of stirred tanks having multiple impellers. Understanding the interaction between impellers in such stirred tanks is important to understand its implications on the process performance. This study is an attempt to understand the hydrodynamics of a batch stirred tank having three Rushton turbine impellers by conducting experiments and Computational Fluid Dynamics (CFD) simulations. Mixing time and vortex depth are measured experimentally at different rotational speeds and gas flow rates. To have detailed insights into the hydrodynamics, a CFD model of the stirred tank is developed and validated with experimental data of vortex depth