CFD simulation of hydrodynamics and mixing performance in dual shaft eccentric mixers

[Display omitted] This work aims to systematically study hydrodynamics and mixing characteristics of non-Newtonian fluid (carboxyl methyl cellulose, CMC) in dual shaft eccentric mixer. Fluid rheology was described by the power law rheological model. Computational fluid dynamics was employed to simulate the velocity field and shear rate inside the stirred tank. The influence mechanism of the rotational modes, height difference between impellers, impeller eccentricities, and impeller types on the flow field have been well investigated. We studied the performance of different dual-shaft eccentric mixers at the constant power input with its fluid velocity profiles, average shear strain rate, mixing time and mixing energy. The counter-rotation mode shows better mixing performance than co-rotation mode, and greater eccentricity can shorten mixing time on the basis of same stirred condition. To intensify the hydrodynamic interaction between impellers and enhance the overall mixing performance of the dual shaft eccentric mixers, it is critical to have a reasonable combination of impellers and an appropriate spatial position of impellers.