Simplified Calculation of Mixing and Suspending Processes in Agitated Vessels – Part II: Examples of Application

Abstract

Mixing processes in agitated vessels with different stirring systems are simulated using a cell model. The model takes the fluid velocity and fluid turbulence, as well as the diffusion and the sedimentation velocity of the particles into account. The two-and three-dimensional behaviors of single particles and collectives of particles in the vessels, respectively, are discussed in terms of different aspects. The calculated concentration distributions are compared with some measurements from the literature. Furthermore, a user interface developed for the calculation program, is introduced. , it is possible to connect both models using an advanced velocity model. However, these connections are not applied for the calculation of the axial flow impeller presented here.The tangential velocity at the exterior of the stirrer jet stream does not depend on the axial direction for the unbaffled case b and for the calculation model used here 1) . The model results in a tangential velocity being totally locally independent for the cases c 1 and c 2 , Fig. 3. Conditions of Mass AdditionThe temporal progress of mixing processes strongly depends on the location of the addition [5]. In order to solve problems that are relevant in practice, different possibilities of addition can be chosen in the program. In general, particles having a density different from the fluid are added with a volume fraction of 60 %, for the calculation of collectives of particles following the value of closely packed spheres, if no other value is defined. The volume of the substance added should not affect the filling level.