2012 Volume 45 Issue 5 Pages 315-323
Two-dimensional particle image velocimetry (PIV) and digital image analysis are used to quantify the hydrodynamics of gas–liquid flow in a cubic tank with a flat square base (length T=230 mm). The fluid is stirred by a half elliptical disk turbine (HEDT) of diameter D=77 mm. Flow fields at 8 different gas holdups from 2.24 to 5.78% are investigated. The gas is injected into the tank through a syringe needle. The measurements are taken in a plane which is 2 mm from the wall and the radial velocity could be ignored compared to the axial and tangential velocity. Therefore, the flow field is considered to be two-dimensional. The results show that the liquid mean velocity and turbulent kinetic energy (TKE) decrease with an increase in gas holdup, and the turbulent kinetic energy dissipation first increases, then decreases with an increase in gas holdup.