Numerical Simulation of the Motion of Solid Particles in a Stirred Tank

The motion of solid spherical particles in a baffled stirred tank is investigated numerically. The turbulent flow is simulated by using a two-phase model with the standard k-epsilon turbulence model. The standard k-epsilon turbulence model has been used to simulate single and multi-phase flows in stirred tanks. In the present work, this model is used to evaluate the liquid mixing time. A multiple reference frames (MRFs) method is employed to simulate the rotation of impeller in the tank. Eulerian-Eulerian and Eulerian-Lagrangian approaches are implemented to simulate a dense solid-liquid suspension. The particle size is 264 mu m concludes the volume fraction of 10 %. Also, the impeller rotational speed is in the range of 5 to 16.7 rps. The results show that the mixing quality increases with the impeller rotational speed. It is revealed that the Eulerian-Eulerian approach that captures the solid-liquid interface is more appropriate model to predict the mixing process than Eulerian-Lagrangian one (point-particle method) for a dense suspension.