Einsatz der Stereo‐PIV zur Optimierung von Suspendiervorgängen

Investigation and Visualization of Flow Fields in Stirred Tank Reactors Using a Fluorescence Tracer Method

“…In comparison to PIV measurements, the most common method for quantitative flow field investigations, the fluorescence tracer method features significantly less measurement expense, as the laser system and the related safety requirements are not present here. The primary strength of the PIV, however, lies within the quantitative measurement of local flow velocity vectors as well as other quantities such as the turbulent kinetic energy (TKE) [20,50], which the fluorescence tracer method cannot provide at its current state. However, the presented results allow insight specifically in the flow direction as well as ''dead zones'' inside the reactor.…”

Flow Field Investigations of Two‐Stage Stirrer Configurations Combining Axially and Radially Conveying Turbines

“…This non-invasive, laser-optical measurement technique allows insight into the velocity of liquid or gas flows. Measurements take place in a specifically constructed measurement station that has been used for multiple studies featuring a variety of (laser-)optical methods already [1,9,19,[24][25][26][27].…”

“…Seeding particles are added into the fluid that are supposed to follow the flow ''slip-free''. In case of these liquid applications, polyamide particles with a mean diameter of 50 mm (PSP-50), supplied by Dantec Dynamics A/S, Denmark, have proven their suitability in multiple studies [1,9,25,27].…”

“…suspension processes, with an axial impeller near the reactor bottom, responsible for lifting up particles, and a radial impeller as the upper stage, for large‐scale particle distribution 1;…”

“…Comprehensive investigations of these systems and their specific flow fields as well as design and construction recommendations are therefore still lacking. Potential applications of these combinations of different impeller types may include: -suspension processes, with an axial impeller near the reactor bottom, responsible for lifting up particles, and a radial impeller as the upper stage, for large-scale particle distribution [1]; -biotechnological fermentation processes, with a radial impeller located near the gas inlet, for bubble dispersion, and an axial impeller for gas distribution across the volume [2][3][4][5][6][7][8]; -processes involving internal heat exchangers; as shown by Ja ¨hrling and Schultz, single-stage impellers are rarely sufficient to ensure the required flow velocity and turbulence for adequate heat transport for multiple industrially used heat exchanger internal geometries [9]. Due to the mentioned lack of knowledge and design recommendations, assumptions how different impeller types can be combined reasonably have to be made.…”