A Large Eddy Simulation for the mixing of miscible liquids with high viscosity contrasts in a turbulently stirred vessel
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This paper compares the blending time predictions of a Large Eddy Simulation with a Lattice Boltzmann Method when predicting the blending time of a series of mixing processes involving two miscible liquids with a physical property difference, articularly those with high viscosity contrasts. The performance of the numerical model is assessed based on blending time data obtained from an in-house Electrical Resistance Tomography (ERT) technique [1], detecting the conductivity contrast of the two liquids mixed in a 2.6 litre fully baffled vessel, stirred by a Rushton turbine operating in a turbulent regime. Using a scalar transport model coupled with Lattice Boltzmann Large Eddy Simulation (LB-LES) solver, the background flow field parameters are assessed and compared with existing experimental data. This paper intends to shed light on the mixing mechanisms of miscible liquids under the mentioned circumstances to contribute to the understanding of modelling limitations of such approaches which is key in accurately designing mixing processes. The results presented indicate a close conformal of the model tested with the experimentally determined trends of dimensionless blending time as a function of fluid properties.
