Mixing characteristics in a vessel equipped with cylindrical stirrer

In this work, the mixing characteristics in a vessel equipped with a cylindrical stirrer were investigated experimentally and numerically in an unbaffled tank. The cylinder stirrer is a cylinder with four openings and four wing panels symmetrically distributed. Mixing characteristics were measured by adding second tracer. The shaft-torque method was applied for the power consumption measurement. Tap water was used as the continuous phase and starch solution was the dispersed phase. CFD investigations on the flow field, power consumption, as well as mixing time, have been performed. Three-dimensional time-dependent flow and mixing prediction have been carried out using Slide Mesh (SM) method embodied CFD package FLUENT 6.3. Mixing time studies were done using a simulated tracer injection experiment. The comparisons of the power numbers and mixing times for a cylinder stirrer, a Rushton turbine and a propeller turbine, have been carried out. It is suggested that the cylinder stirrer is relatively more energy efficient compared with the Rushton turbine and the propeller turbine.