Felix Kexel, M.Sc.

Eißendorfer Str. 40, Building N, Room 1.082

Telephone +49 40 42878-4663

E-Mail: Felix Kexel, M.Sc.


Research

DFG Priority Project 1740 - "Reactive Bubbly Flows"

 

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

Applying measuring techniques as Particle Image Velocimetry (PIV), Laser Induced Fluorescence (LIF) or imaging UV-VIS Spectroscopy to obtain information on velocity and concentration fields of primary and secondary products in the wake of rising gas bubbles


Education

Graduate Teaching Assistant

  • Fluid Mechanics in Process Engineering (Winter term)

 


Supervised Theses

Current Thesis:
  • "Experimentelle Untersuchung des Einflusses der Fluiddynamik auf eine kompetitiv-konsekutive Reaktion in einer Hele-Shaw Zelle" [Working Title], Rene Weglewski, Master thesis
Finished Thesis:
  • "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 Selonoid 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

  • Kexel, F.; Bertram, S.; Mehrbach, 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
  • 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; 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
  • 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


Publications

[162573]
Title: Investigation of Reactive Bubbly Flows in Technical Apparatuses. <em>Reactive Bubbly Flows. Fluid Mechanics and Its Applications</em>
Written by: 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.;
in: (2021).
Volume: <strong>128</strong>. Number:
on pages: 621-642
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DOI: https://doi.org/10.1007/978-3-030-72361-3_24
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Abstract: In the previous chapters it has been shown that the fluid dynamic conditions in bubbly flows might affect a competitive consecutive chemical reaction concerning yield and selectivity. The question arises if this results are transferable to technical apparatuses with industrial conditions. To clarify this question, the competitive consecutive DBED reaction system dissolved in tetrahydrofuran is transferred to an industrial apparatus that has been already used for a cyclohexane oxidation. First, it is shown with the Taylor bubble experiments that the DBED reaction system can be used as a model system for competitive consecutive reactions with adjustable kinetics. Afterwards, the DBED reaction system is applied to the technical apparatus. It shows that the yield and selectivity of the DBED reaction in the technical apparatus depends on the bubble size distribution and therefore potentially on the local wake structure. Even though numerical simulations with the Euler-Lagrange approach are already able to predict the formation of product and byproduct of a competitive consecutive reaction, the local flow structure within the bubble wake and its potential influence on yield and selectivity can not be covered so far.