The fluid-dynamic behaviour of high-aspect-ratio vessels stirred with multiple axial impellers was investigated. For this purpose, liquid homogenization experiments were carried out: a non- reactive tracer was injected at the top of the vessels and its concentration course was measured at severa! heights. Four types of agitators were used: six pitch-bladed ( 45°) turbines pumping down and up and A3 I O and A3 I 5 hydrofoil impellers; three identica! agitators were mounted on the same shaft. The response curves were interpreted with the axial dispersion model and the parameter De was evaluated. The experimental curves measured at the various heights were fitted fairly well by the curves calculated with the model. Correlations of the dimensionless parameter De!ND2 with Reynolds number are presented and discussed.
JAHODA et al. (Sat,) studied this question.