Non‐ideal flow parameters for viscous fluids flowing through stirred tanks

AbstractResidence time distribution functions for the flow of viscous fluids (6‐100 poises) through mechanically stirred tanks have been evaluated experimentally for various flowrates and stirrer speeds in three tank sizes, in geometrically similar systems. The results have been examined in terms of a mixed model suggested by visual observations of flow patterns within the tanks. A mechanistic model consisting of a dual backmix region and deadspace in series with a plug‐flow region was found to be compatible with these results. It was also found that previously tested models for stirred‐tank systems can be represented by limiting cases of this more general model. Further, it is shown that the parameters of the model can be expressed in useful engineering correlations derivable from the operating variables. Preliminary results on the effects of non‐Newtonian flow on the validity of the model are also presented. Application of the model to chemical reactor design is illustrated for first‐order reaction kinetics.