CFD Simulations of a Large-Scale Seed Precipitation Tank Stirred with Multiple Intermig Impellers

The three-dimensional multiphase flow in a large-scale seed precipitation tank stirred with multiple Intermig impellers was simulated by CFD method. The flow field, solid particles distribution and power consumption were numerically analyzed by adopting Eulerian Granular Model (GEM) and standard k-e turbulence model. The tank was improved by lengthening the lowest impeller and adopting sloped baffles which largely promoted the solids suspension and fluid mixing. In the original tank, the maximum of relative solid concentration difference in the whole tank was less than 5% at the minimum rotational speed of 4.8r/min. Although the lowest lengthened impeller cost more power, the minimum rotational speed could be down to 3.8r/min. So in the improved tank, about 40% power could be saved to achieve the same mixing effect. The results have important meaning to industrial design and optimization.