A stirred vessel, equipped with a turbine impeller in its center, is maintained in steady state by continuously introducing two miscible liquids. By means of suitable electronic equipment, the temporal concentration fluctuations are measured at several locations in the vessel, i.e., the inlet, the lower feed to the impeller, the flow ejected by impeller, the lower vortexing zone, the upper vortexing zone, and the outlet.
The goodness of mixing is expressed by a statistical term, the temporal concentration fluctuation intensity, i.e.
I= σ²_a/a(1-a)
The intensity ranges from zero (complete mixing) to unity (complete segregation).
The decay of the intensity in each flow zone, i.e., the inlet zone and the impeller zone, and the overall mixing performance are studied with parameters of flow rate and impeller speed. The experimental results are in fair agreement with the proposed theories, of which the derivations are strongly based on the mature of flow pattern in the stirred vessel.