Numerical simulation of mixing process in stirred tank of blender truck

In order to overcome the shortage of semi-empirical design of the stirred tank of blender truck to certain extension and guide its enlargement design, the mixing process inside the stirred tank of blender truck with solid-liquid two-phase flow was numerically simulated in the unsteady state based on Fluent. The unstructured grid, standard k-epsilon turbulent model, Eulerian multiphase model, sliding mesh and SIMPLE algorithm were used to study the flow field, the mixing power, the distribution law of the solid volume in the stirred tank and the mixing time. The results show that the flow characteristics in the flow field are influenced by the upper impeller and the lower impeller. The key to increase the mixing efficiency is to reduce tangential velocity, increase axial and radial velocity. The relationships of agitation speed with torque and power correspond to the conventional characteristics of agitator blade. There are still some regions which do not have the main loop after the flow field distributes uniformly. In those regions, the volume fraction of the solid phase is lower, and the flow field can be optimized by increasing the length of baffles. By monitoring the concentrations of three typical points, the mixing time can be obtained which can predict the mixing time in the practical technology. The results are of importance to the optimization and design of stirred tank of blender truck.