Determination of Kinetics for Reactive Bubbly Flows Using SuperFocus Mixers
First published in
Number in series
in: Reactive Bubbly Flows - Final Report of the DFG Priority Program 1740: Fluid Mechanics and its Applications 128: 479-506 (2021)
For the well-defined investigation of reactive bubbly flows it is crucial to know the kinetics of the chemical reaction steps as detailed as possible which means that the hindrance due to mixing should be minimized (intrinsic kinetics). This is especially difficult for fast chemical reactions that are addressed in this book. Therefore, to distinguish between convective mixing and diffusion a tool should be used that enables an optical access to visualize and detect the instant mixing on a microscale and the comparison with numerical simulations. Furthermore, this tool should be easy to handle for chemical engineers and inexpensive. A SuperFocus mixer in a continuous-flow setup is used for this purpose, in which two mixable liquid streams are mixed, with the gas phase dissolved in one of the streams. The results are compared with a classical stopped-flow apparatus. Because chemical reactions are generally following a complex reaction network with many reaction steps and intermediates that are mostly difficult to detect, the measurement of the formation of the relevant products and by-products is a difficult task by its own. Spectroscopic methods including absorption or fluorescence measurements are used here to detect the formation of the relevant products and to determine the gross kinetics for the relevant reaction steps. Finally, the experimental results are used to adapt direct numerical simulations for an estimation of the corresponding diffusion coefficients and reaction constants.