(431b) Characterization of Vortex Formation and Blend Time in Unbaffled Tanks

Vortex formation in unbaffled mixing tanks has not been characterized in previous literature studies. This work has characterized vortex formation as a function of the inverse Froude number and Reynolds number. Additionally blend time studies have been performed using conductivity measurements. The data was collected at liquid level heights ranging from 0.75 to 1.75 of the tank diameter, impeller speeds from 150 RPM to 800 RPM, axial and radial impellers, and tank diameters of 8 inches to 2 feet. The following correlation, based on Grenville was obtained: 5.66 = N_p^1/3 × Re × Fo where Fo is the Fourier number.