Mixing performance induced by coaxial flat blade-helical ribbon impellers rotating at different speeds

The mixing performance (pumping, dispersion capabilities, power consumption) of a new dual impeller mixer composed of a disc turbine and a helical ribbon impeller mounted on the same axis but rotating at different speeds is investigated. The methodology is based on a blend of experimental measurements and 3D numerical simulations in the case of Newtonian and non-Newtonian shear-thinning fluids. It is shown that the dual impeller mixer outperforms the standard helical ribbon in terms of top-to-bottom pumping when the fluid rheology evolves during the process. The power consumption of this new mixer is also studied which allows to derive a generalized power curve.