Vortex depth in mixed unbaffled vessels

An experimental investigation of vortex depth in an unbaffled cylindrical vessel with co-axial agitation was made. Five types of impellers: standard six-blade disc turbine, flat six-blade turbine, pitched six-blade turbine, pitched three-blade turbine and anchor agitator were tested. Turbine impellers were investigated in two positions (H₂ = d and H₂ = d/3). On the basis of theoretical analysis, the dimensionless vortex depth was statistically correlated as a function of Froude and Galileo numbers and a relative impeller size. Liquid viscosity and impeller size variations were reflected in the value of the Galileo number which was within the range 4 × 10⁵ – 5 × 10¹⁰. The vessel diameters used in the experiments were, D= 0.15, 0.20, 0.30, 0.40 and 0.64 m.