Dr.-Ing. Felix Kexel

Eißendorfer Str. 38

Building O, Room 1.008

21073 Hamburg

Phone +49 40 42878 - 4663

Mail Felix Kexel


How are the different timescales of fluid dynamic mixing, mass transfer and reaction kinetics impacting the yield and selectivity of competitive-consecutive gas-liquid reactions?

Applying measuring techniques as Particle Image Velocimetry (PIV), Particle Tracking Velocimetry (PTV), Laser Induced Fluorescence (LIF) or imaging UV-VIS Spectroscopy to obtain information on velocity and concentration fields around reactive bubbles to understand the complex interplay of fluid dynamics, mass transfer and chemical reactions.

Research Projects
  • Mixing structures in bubble wakes of single bubbles and bubble swarms and their influence on gas-liquid mass transfer and chemical reaction

  • I3 Junior Project in collaboration with Hannah Buchholz (IPI) and Dr.-Ing. Jürgen Fitschen funded by the TUHH: Tomographic Reconstruction of Spherical and Irregularly Shaped Bubbles for Precise Determination of the Interfacial Area

  • DFG Priority Project 1740 – Reactive Bubbly Flows


Undergraduate courses

  • Fundamentals of Fluid Mechanics (Fluid Mechanics I)

Supervised Theses

  • "Design of a transparent MRI ready setup for the determination of bubble surfaces" [working title], Ole Simmering, Master thesis, in collaboration with Hannah Buchholz (IPI)

  • "Vergleich von Strömungs- und Konzentrationsfeldern in einem Flachbettreaktor mittels Particle Image Velocimetry und Laserinduzierter Fluoreszenz", Rene Weglewski, Master thesis, 2023

  • "Experimentelle Untersuchung von Konzentrations- und Strömungsfeldern im Nachlauf einer reaktiven Taylor Blase", Anahita Radmehr, Master thesis, 2023

  • "Experimentelle Untersuchung der 3–dimensionalen Strömungsstrukturen in einer Blasenströmung mittels 4D–PTV", Yara Kappes, Master thesis, 2022

  • "Taylor Bubbles in Organic Solvents", Sina Bertram, Bachelor thesis, 2022

  • "Computation of Unsteady Mass Transfer in Bubble Wakes by Means of 2D Lagrangian Analysis", Lotta Kursula, Master thesis, 2022

  • "Anwendung der Penetrationstheorie auf lokale Stofftransportprozesse an Taylor Blasen", Benjamin Rahimian, Bachelor thesis, 2022

  • "Characterization of the fluid dynamic properties of a Methanol based chemical reaction", Noah von Schnitzler, Bachelor thesis, 2021

  • "Taylor Bubble Generation Using a Solenoid Valve", Tarlan Ramazanli, Project Work 2021

  • "Detailed investigations of bubble trajectories in clean and contaminated systems", Sam Dors, Bachelor thesis, 2020

  • "Determination of mass transfer coefficients from single Taylor bubbles in contaminated systems – a study for industrial applications", Aaron Kaulbarsch, Bachelor thesis, 2019

  • "Experimentelle Analyse des Einflusses von organischen Lösemitteln auf die Hydrodynamik von Taylorblasen am Bespiel von Acetonitril", Carolin Lohmann, Bachelor thesis, 2019

Oral and Poster Presentations


  • Fitschen, J.; Kexel, F.; Hofmann, S.; Kuschel, M.; Hoffmann M.; Wucherpfennig, T.; Schlüter, M.:" Hydrodynamic Characterization and Identification of Heterogeneities in Stirred Tank Reactory by Means of 4D Particle Trajectories", 11th International Conference on Multiphase Flows, Kobe, Japan, 2023, oral presentation

  • Radmehr, A; Kexel, F.; von Kameke, A.; Hoffmann, M.; Schlüter, M.: "Local Velocity Fields at Taylor Bubbles in Methanol" 11th Workshop Chemical and Biological Mico Laboratory Technology 2022, Ilmenau, 2022, oral presentation

  • Kexel, F.; von Kameke, A.; Hoffmann, M.; Schlüter, M.: "Fluid Dynamics of Taylor Bubbles in Organic Solvents" ProcessNet Jahrestreffen Mehrphasenströmungen, Mechanische Flüssigkeitsabtrennung & Zerkleinern und Klassieren 2022, virtual, 2022, oral presentation

  • Kexel, F.; von Kameke, A.; Hoffmann, M.; Schlüter, M.: "Investigation on Velocity and Concentration Fields at Taylor Bubbles in a Reactive Bubbly Flow" Dispersed Two-Phase Flows 2021, virtual, 2021, oral presentation

  • Kexel, F.; von Kameke, A.; Hoffmann, M.; Schlüter, M.: "Influence of Fluid Dynamics on the Selectivity of Competitive Consecutive Gas Liquid Reactions" 13th European Congress of Chemical Engineering (ECCE13), virtual, 2021, oral presentation

  • Kexel, F.; von Kameke, A.; Colombi, R.; Rüttinger, S.; Hoffmann, M.; Schlüter, M.: "Inverstigation of Reactive Mass Transfer Processes at Single Rising Bubbles by Means of Time-Resolved Scanning Laser Induced Fluorescence" 12th European Congress of Chemical Engineering (ECCE12), Florence, Italy, 2019, oral presentation

  • Kexel, F.; Rüttinger, S.; Kastens, S.; von Kameke, A.; Oßberger, M.; Hoffmann, M.; Schlüter, M.: "Does the wake structure in bubbly flows affect yield and selectivity of a competitive consecutive reaction? – A Taylor-Bubble study" ProcessNet Jahrestreffen Reaktionstechnik & Mehrphasenströmungen 2019, Würzburg, 2019, oral presentation

Poster Presentations

  • Merbach,T.; Mockus, B.; Minamitani, K.; Kexel, F.; Schlüter, M.; Valluri, P.; Hayashi, K.; Tomiyama, A.:" Development of a Correlation for the Terminal Rising Velocity for 2D-Bubbles in Unconfined Domain", 11th International Conference on Multiphase Flows, Kobe, Japan, 2023, poster presentation

  • Kexel, F.; Bertram, S.; Merbach, T.; von Kameke, A.; Hoffmann, M.; Tomiyama, A.; Schlüter, M.: "Influence of Taylor Bubble Shapes on Wake Structures", 4th International Symposium on Multiscale Multiphase Process Engineering, Berlin, 2022, poster presentation

  • Kexel, F.; von Kameke, A; Hoffmann, M.; Schlüter, M.: "Optimization of Chemical Reactions with Tailored Flow Strucures" ProcessNet Jahrestreffen Reaktionstechnik 2021, virtual, 2021, poster presentation

  • Kexel, F.; von Kameke, A; Hoffmann, M.; Schlüter, M.: "Investigation of the influence of fluid dynamics on the selectivity of fast gas-liquid reactions by means of high speed imaging UV/VIS spectroscopy at a Taylor bubble setup" ProcessNet Jahrestreffen Mehrphasenströmungen & CFD 2021, virtual, 2021, poster presentation



  • Frey, T.; Kexel, F.; Grabellus, M.; My Le, X.; Hoffmann, M.; Herbstritt, F.; Grünewald, M.; Schlüter, M.; (2024). Local analysis of micro mixing for the Villermaux-Dushman protocol by using the imaging UV-Vis spectroscopy. Chemical Engineering Research and Design. [Abstract] [doi]

  • Perçin, Z.; Kursula, L.; Löfgren, E.; Byström, E.; Kexel, F.; Bubenheim, P.; Schlüter, M.; Liese, A. (2024). Intensification of a Biocatalytic Oxidation under Fine Bubble Aeration in a Rotating Bed Reactor. Biochemical Engineering Journal. [Abstract] [doi]


  • Kexel, F. (2023). On the influence of wake structures on competitive chemical reactions at Taylor bubbles.


  • Frey T.; Kexel F.; Dittmer K.R.; Bohne S.; Hoffmann M.; Trieu H.K.; Schlüter M. (2022). A Novel Approach for Visualizing Mixing Phenomena of Reactive Liquid-Liquid Flows in Milli- and Micro-Channels. Frontiers in Chemical Engineering. 4. 874019 [Abstract] [doi]

  • Kursula, L.; Kexel, F.; Fitschen, J.; Hoffmann, M.; Schlüter, M.; Kameke, A.v.; (2022). Unsteady Mass Transfer in Bubble Wakes Analyzed by Lagrangian Coherent Structures in a Flat-Bed Reactor. Processes. 10. (12), [Abstract] [doi]


  • Böhm, L.; Merker, D.; Strassl F.; Herres-Pawlis, S.; Oßberger, M.; Klüfers P.; Schindler, S.; Guhathakurta, J.; Grottke, D.; Simon, S.; Rinke, G.; Hlawitschka, M.; von Kameke, A.v.; Kexel, F.; Schlüter, M.; Gast, S.; Tuttlies, U.; Nieken, U.; Hillenbrand, D.; Marschall, H.; Weiner, A.; Bothe, D.; Kraume, M.; (2021). Chemical Reactions at Freely Ascending Single Bubbles. 128. 545-581 [Abstract] [doi]

  • Gast, S.; Tuttlies, U.; Laurini, L.; Kexel, F.; Merker, D.; Böhm, L.; Taborda M. A.; Sommerfeld, M.; Kraume, M.; Schlüter, M.; Herres-Pawlis, S.; Nieken, U.; (2021). Investigation of Reactive Bubbly Flows in Technical Apparatuses. 128. 621-642 [Abstract] [doi]

  • Kexel, F.; Kameke, A.v.; Hoffmann, M.; Schlüter, M. (2021). The influence of fluid dynamics on the selectivity of fast gas–liquid reactions in methanol. Chemical Engineering and Processing - Process Intensification. [Abstract] [doi]

  • Kexel, F.; Kameke, A.v.; Tenhaus, J.; Hoffmann, M.; Schlüter, M. (2021). Taylor bubble study of the influence of fluid dynamics on yield and selectivity in fast gas-liquid reactions. Chemie Ingenieur Technik. 93. (5), 830-837 [Abstract] [doi]

  • Kexel, F.; Kastens, S.; Timmermann, J.; Kameke, A. v.; Schlüter, M. (2021). Experimental Investigation of Reactive Bubbly Flows—Influence of Boundary Layer Dynamics on Mass Transfer and Chemical Reactions. 267–307 [Abstract] [doi]

  • Schlüter, M.; Kexel, F.; Kameke, A. v.; Hoffmann, M.; Herres-Pawlis, S.; Klüfers, P.; Oßberger, M.; Turek, S.; Mierka, O.; Kockmann, N.; Krieger, W. (2021). Visualization and Quantitative Analysis of Consecutive Reactions in Taylor Bubble Flows. 507–543 [doi]


  • Kexel, F.; Kameke, A.v.; Oßberger, M.; Hoffmann, M.; Klüfers, P.; Schlüter, M. (2020). Bildgebende UV/VIS Spektroskopie zur Untersuchung des Einflusses der Fluiddynamik auf die Selektivität und Ausbeute von schnellen konkurrierenden konsekutiven gasflüssig Reaktionen. Chemie Ingenieur Technik. 93. (1-2), 297-305 [Abstract] [doi] [www]