Une methode experimentale d'evaluation globale du pompage d'un agitateur Application au melangeur Maxblend(TM) en milieux newtonien et non-newtonie

This investigation introduces an experimental method to determine the macro pumping capacity of an impeller in a transparent vessel using a decolorization method, contrary to commonly used experimental methods such as Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV). This new inexpensive and easy-to-use method can be employed to quickly fill the lack of data available in the literature about geometrical effects on the global pumping efficiency of an impeller. This method was first applied to three well-known mixing systems and a Newtonian fluid to assess its reliability and accuracy: a six blades Rushton turbine (RT), a pitched blade turbine (PBT) with four 45° blades, and a three-blade hydrofoil propeller (HP). The global pumping capacity of the Maxblend(TM) impeller is then evaluated for both Newtonian and non-Newtonian fluids and compared to the other impellers in the transient to the turbulent regime. As results, considering the global pumping number normalized by the power consumption (Nq*g), the hydrofoil appears to be the most efficient (Nq*g = 2.8) in the fully turbulent regime. However, in terms of mixing time, the Maxblend(TM) impeller shows the best results over the entire range of Reynolds numbers. Finally, the shear-thinning behavior of the non-Newtonian fluid used does not affect the Maxblend(TM) impeller pumping and mixing capacity for Reynolds numbers below 80.;Keywords: experimental method, global pumping capacity, Maxblend(TM) impeller, Newtonian, non-Newtonian.