Particle image velocimetry technique was used to analyze the trailing vortices and elucidate their relationship with turbulence properties in a stirred tank of 0.48 m diameter

agitated by four different disc turbines

including Rushton turbine

concaved blade disk turbine

half elliptical blade disk turbine

and parabolic blade disk turbine.Phase-averaged and phase-resolved flow fields near the impeller blades were measured and the structure of trailing vortices was studied in detail.The location

size and strength of vortices were determined by the simplified λ

2

-criterion and the results showed that the blade shape had great effect on the trailing vortex characteristics.The larger curvature resulted in longer residence time of the vortex at the impeller tip

bigger distance between the upper and lower vortices and longer vortex life

also leads to smaller and stronger vortices.In addition

the turbulent kinetic energy and turbulent energy dissipation in the discharge flow were determined and discussed.High turbulent kinetic energy and turbulent energy dissipation regions were located between the upper and lower vortices and moved along with them.Although restricted to single phase flow

the presented results are essential for reliable design and scale-up of stirred tank with disc turbines.