H. Nirschl, L.E. Spelter, X. Romani Fernandez

InTech

Applied Computational Fluid Dynamics

Book chapterExcerpt from introduction[...]The emphasis of the work presented is the evaluation of the efficiency of the acceleration geometry and the prediction of the axial flow profile in the centrifuge. In centrifugation technology, the prediction of the separation efficiency is often restricted to the cut size, the smallest particle size that can settle on the bowl wall at certain operating conditions. In a centrifuge, the highest velocities occur in tangential direction but, due to the throughput, a secondary flow in the axial direction appears. The tangential velocity creates the centrifugal force acting on the particles and the flow in the axial direction determines the residence time of particles in the bowl. Thus it is necessary to know the flow patterns in a centrifuge in order to calculate its separation capability. Often the predicted cut size of a centrifuge diverges from the real separation efficiency due to the fact that the assumptions of the analytical models are not strictly valid for industrial process conditions. The deviation is caused by the complex shape and internal assemblies of industrial solid bowl centrifuges, which create complex flow patterns. Hence estimating these flow patterns, as well as measuring them, is complicated. [...]

centrifuge, DEM-CFD, Flow pattern