Institute of Multiphase Flows

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Dr.-Ing. Jens Timmermann

Am Irrgarten 7, Building Q, Room 119
Telephone +49 40 42878-4662
E-Mail: M.Sc. Jens Timmermann

Project:

"Experimental Investigation of Reactive Bubbly Flows - Influence of Boundary Layer Dynamics on Mass Transfer and Chemical Reactions"

In chemical process engineering often a gaseous substance has to be mixed with a continuous liquid phase in order to perform a reaction with high yield and selectivity (e.g. oxidation or hydrogenation). For this purpose, the use of well mixed bubble flows is preferred, in which the gaseous phase is dispersed in the liquid phase. The timescales of mixing are especially determined by the transport processes in the boundary layer close to the phase boundary and by the bubble swarm-turbulence. Tuning the transport timescales and the timescales of the chemical reactions can lead to a considerable potential for optimization of the actual yield and selectivity. Thus transport processes in the boundary layer and close to interphase of free rising bubbles with a following chemical reaction are experimentally determined and subsequently modeled in the framework of this priority program. Especially the influence of dynamic interface deformation of the bubbles, due to shape dynamics (wobbling), the momentum exchange at the gas-liquid interface (swarm turbulence) and bubble collisions (bouncing) are taken into account. To accurately observe the local transport processes near the phase boundary Time Resolved Scanning Laser Induced Fluorescence (TRS-LIF) and high-resolution Particle Image Velocimetry (PIV) are applied. The fruitful cooperation between chemists, mathematicians and experimentalists within the priority program will give a substantial contribution to understand the complex interaction between boundary layer dynamics, mass transfer and chemical reaction near the phase boundary.

detailed Project description

part of the SPP 1740: Reactive Bubbly Flows (German Research Foundation; DFG)

SPP 1740 homepage: reactive bubbly flows

supported by the German Research Foundation (DFG), reactive bubbly flows (SPP 1740; SCHL 617/12-1)

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Recording of the concentration fields around a 10 mm oxygen bubble rising in a solution of Dichlorotris(1,10-phenanthroline)ruthenium(II) hydrate and DI water obtained with time-resolved scanning LIF

Publications:

Paper:

Hermann, P.; Timmermann, J.; Hoffmann, M.; Schlüter, M.; Hofmann, C.; Löb, P.; Ziegenbalg, D.: Optimization of a Split and Recombine Micromixer by Improved Exploitation of Secondary Flows, Chemical Engineering Journal, 11/2017, accepted for publication. DOI: 10.1016/j.cej.2017.11.131

Kastens, S., Timmermann, J., Strassl, F., Rampmaier, R. F., Hoffmann, A., Herres-Pawlis, S., Schlüter, M.: Test system for the investigation of reactive Taylor bubbles. Chemical Engineering & Technology. Accepted Article.DOI: 10.1002/ceat.201700047

Sellin, D; Hiessl, R.; Bothe, M.; Timmermann, J.; Becker, M.; Schlüter, M.; Liese, A.: Simultaneous local determination of mass transfer and residence time distribuations in organic multiphase systems. Chemical Engineering Journal, 2017, 321, pp. 635-641, DOI: 10.1016/j.cej.2017.03.150.

Mierka, O., Munir, M., Spille, C., Timmermann, J., Schlüter, M. Turek, S. (2017), Reactive liquid flow simulation of micromixers based on grid deformation techniques. Chemical Engineering & Technology. Accepted Article. DOI: 10.1002/ceat.201600686

Timmermann, J., Hoffmann, M., Schlüter, M. (2016). Influence of bubble bouncing on mass transfer and chemical reaction. Chemical Engineering & Technology. 2016. 39(10). pp. 1955-1962 DOI: 10.1002/ceat.201600299

Strassl, F., Timmermann, J., Schlueter, M., Herres-Pawlis, S. (2016).Kinetik der Sauerstoffaktivierung. GIT Labor-Fachzeitschrift. 39-41

Oral Presentations:

Jahrestreffen der Fachgruppen Computational Fluid Dynamics und Mehrphasenströmungen, 2015, Lueneburg, Germany: "Einfluss von Blasenkollisionen in Blasenströmungen auf Stofftransport und chemische Reaktionl", Jens Timmermann, Marko Hoffmann, Michael Schlueter

Jahrestreffen der ProcessNet-Fachgruppen Agglomerations- und Schüttguttechnik, Mehrphasenströmungen und Computational Fluid Dynamics, 2016, Bingen, Germany: "Experimentelle Analyse der Grenzschichtdynamik in Blasenströmungen", Jens Timmermann, Marko Hoffmann, Michael Schlueter

9th International Conference on Multiphase Flows, 2016, Florence, Italy: "Influence of bubble bouncing on mass transfer and chemical reaction", Jens Timmermann, Marko Hoffmann, Michael Schlueter

Symposium on Non-Invasive Measuring Tools and Numerical Methods for the Investigation of Non-Reactive and Reactive Gas-Liquid Flows, FERMaT-SPP1740 Symposium Toulouse 2016, France: "Influence of bubble bouncing on mass transfer and chemical reaction", Jens Timmermann, Marko Hoffmann, Michael Schlueter

Jahrestreffen Dresden - Jahrestreffen der ProcessNet-Fachgruppen Mehrphasenströmungen, Partikelmesstechnik, Zerkleinern und Klassieren, Computational Fluid Dynamics, Mischvorgänge und dem TAK Aerosoltechnologie, 2017, Dresden, Germany: "Einfluss der Grenzschichtdynamik auf den Stofftransport und chemische Reaktionen", Jens Timmermann, Marko Hoffmann, Michael Schlueter

Poster Presentations:

ESCRE 2015 - European Symposium on Chemical Reaction Engineering, 2015, Fuerstenfeldbruck, Germany: "Experimental analysis of boundary layer dynamics inbubbly flows", Jens Timmermann, Marko Hoffmann, Michael Schlueter

MMPE2017 -  Third International Symposium on Multiscale Multiphase Process Engineering, 2017, Toyama, Japan: "Influence of boundary layer deformations on mass transfer and chemical reaction", Jens Timmermann, Marko Hoffmann, Michael Schlueter