Novel evaluation method to determine the local mixing time distribution in stirred tank reactors

Stirred tank reactors are frequently used for mixing as well heat- and mass transfer processes in chemical biochemical engineering due to their robust operation extensive experiences the past. However, cell culture like mammalian expression systems, special requirements have be met ensure optimal growth product quality. One of most important ideal transport is a proper performance, characterized typically by global time tmix,global or dimensionless tmix,global·n. As an evaluation method determination, usually determined until tracer signal (e.g. conductivity) has reached constant value after peak been introduced adding salt). A disadvantage this is, that position feeding probe significantly influences detected time. Further on, does not provide any information about spatial temporal ”history” process identify areas mixed poorly form stable compartments. To overcome disadvantage, novel image analysis will presented study detailed characterization taking into account history mixing. The based on experimental determination local distribution using multi-color change caused pH-change bromothymol blue solution. 3 L transparent stirred reactor benchmark experiment. demonstrate suitability new validation numerical simulations, calculation with commercial Lattice-Boltzmann approach (M-Star CFD) performed additionally evaluated regarding distributions. exemplary application simulation shows good agreement corresponding On one hand, can also interesting work, especially validation, other allows much deeper insights behavior compared conventional criteria. For example enables different scales identification micro- macroscopic flow structures. strong influence acid base ratio experiments becomes clearly visible method.