|Title: Experimental Investigation and Modelling of Local Mass Transfer Rates in Pure and Contaminated Taylor Flows Transport Processes at Fluidic Interfaces|
|Written by: Kastens, S.; Meyer, C.; Hoffmann, M.; Schlüter, M.|
|Editor: Bothe, D.; Reusken, A.|
Abstract: In many industrial applications of chemical and bio-chemical engineering, new insights into mass transfer processes across fluidic interfaces are of high interest. Mass transfer processes across gas-liquid interfaces have been investigated for decades to understand the coupling of hydrodynamics and mass transport processes and to describe and correlate them for various gas-liquid flow apparatus and process parameters. The investigation of the linked transport processes and the understanding of their interaction is fundamental for the optimization of multiphase reactors and for the validation of numerical simulations, which are pointing at problems of higher complexity during the last years. One challenge for the investigation of gas-liquid flows is the highly stochastic behaviour of gas bubbles rising in liquids under turbulent flow conditions. For the investigation of local mass transfer processes at fluidic interfaces and the validation of numerical simulations, more well-defined and reproducible conditions are necessary. A suitable setup to study mass transfer at fluidic interfaces under well-defined and reproducible conditions is the gas-liquid flow through a small, straight capillary, called “Taylor bubble” for single bubbles and “Taylor flow” for bubbles in a chain. Taylor flows and Taylor bubbles have ideal properties for detailed investigation on the influence of hydrodynamics and mass transfer at clean and contaminated interfaces, where the shape oscillations are suppressed and the Taylor bubbles are self-centering within vertical channels. Therefore, in this work the local hydrodynamics and mass transfer processes in Taylor flows and at Taylor bubbles have been investigated with laser measurement techniques, to obtain a deeper insight into mass transfer processes at fluidic interfaces. Furthermore, experimental data for the guiding measure “Taylor flow” has been provided. The guiding measure has been established within the SPP 1506 to generate a reliable data basis for the validation of numerical simulations.