The mixing of water and air has been studied in an agitated tank with
narrow baffles. In such an agitated tank, the gas induction could be f
ormed by the dual impellers operated above the critical impeller speed
. Experimental parameters considered mere the impeller speed, the baff
le width, the clearance between lower impeller and tank bottom, the im
peller diameter, the space between two impellers and the liquid level.
Dimensional analysis and data regression gave a good correlation betw
een the mixing time, the tank geometry and operational variables. It w
as found that an increase in impeller speed reduced significantly the
mixing time. Too much reduction of baffle width, a decrease in the imp
eller diameter or a raise of liquid level can increase the mixing time
. However, after gas induction achieved, the clearance between the low
er turbine and the tank bottom has no significant effect on the mixing
time.