Hydrodynamics of a Dual Shaft Mixer with Newtonian and Non-Newtonian Fluids

The hydrodynamic performance of a multi-shaft stirred vessel comprising a Paravisc impeller mounted on central shaft and an off-centred rotor-stator was investigated in the laminar regime with Newtonian and non-Newtonian fluids. The power consumption and the mixing time were determined using torque measurements and a discolouration method, respectively. It was found that the rotor-stator did not influence the power consumption of the Paravisc turbine in relation the poor pumping capacity of the rotor-stator. The overall mixing process and the influence of rotor-stator on the mixing process were investigated. It was found that the rotor-stator not only initiates the mixing early but also improves rate of mixing. To ensure the best mixing efficiency, the present study highlights that the Paravisc needs to be operated in such a way that the contribution of the Paravisc power draw on the overall power consumption is predominant.