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Unsteady Mass Transfer in Bubble Wakes Analyzed by Lagrangian Coherent Structures in a Flat-Bed Reactor. Processes (Basel) 2022. [DOI: 10.3390/pr10122686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
To increase the yield and selectivity in reactive bubbly flows, the gas-liquid interactions have to be understood in depth. In the current fundamental study, flow and concentration data of the wakes of two-dimensional bubbles in an organic solvent are obtained experimentally in a flat-bed reactor. The unsteady mass transport phenomena in these turbulent wakes of two freely rising, two-dimensional bubbles with bubble Reynolds numbers Re=949 and Re=388 are evaluated by analyzing Lagrangian Coherent Structures (LCS). To reveal how LCS govern the transport of dissolved gas in bubble wakes, and therefore affect gas-liquid reactions, LCS in two-dimensional velocity fields are computed and compared with concentration fields of dissolved gas. The analysis of backward Finite Time Lyapunov Exponent (bFTLE) fields reveals coherent fluid dynamic structures for both bubble Reynolds numbers studied. In the higher bubble Reynolds number case, two types of coherent structures are found, which hinder the mixing of the dissolved gas and the liquid bulk. Repelling LCS are found to enclose parcels transported into the vortices, and indicate thus, which fluid parcels can possibly take part in chemical reactions. Due to higher mixing, unveiled by details from the LCS and FTLE analyses, and therefore increased contact area between dissolved gas and fresh liquid, higher yields of reaction products are suggested for the lower bubble Reynolds number case in this two-dimensional study. This is contradicting the rule of thumb that mixing increases for higher bubble Reynolds numbers.
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Almani S, Blel W, Gadoin E, Gentric C. Investigation of single bubbles rising in Newtonian and non-Newtonian fluids inside a thin-gap bubble column intended for microalgae cultivation. Chem Eng Res Des 2021. [DOI: 10.1016/j.cherd.2021.01.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Kemper P, Küstermann E, Dreher W, Helmers T, Mießner U, Besser B, Thöming J. Magnetic Resonance Imaging for Non‐invasive Study of Hydrodynamics Inside Gas‐Liquid Taylor Flows. Chem Eng Technol 2021. [DOI: 10.1002/ceat.202000509] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Philip Kemper
- University of Bremen Department of Chemical Process Engineering Leobener Str. 6 28359 Bremen Germany
| | - Ekkehard Küstermann
- University of Bremen AG in-vivo MR Leobener Str. 6, NW2-C 28359 Bremen Germany
| | - Wolfgang Dreher
- University of Bremen AG in-vivo MR Leobener Str. 6, NW2-C 28359 Bremen Germany
| | - Thorben Helmers
- University of Bremen Department of Environmental Process Engineering Leobener Str. 6 28359 Bremen Germany
| | - Ulrich Mießner
- University of Bremen Department of Environmental Process Engineering Leobener Str. 6 28359 Bremen Germany
| | - Benjamin Besser
- University of Bremen Department of Chemical Process Engineering Leobener Str. 6 28359 Bremen Germany
| | - Jorg Thöming
- University of Bremen Department of Chemical Process Engineering Leobener Str. 6 28359 Bremen Germany
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Lerch M, Weitzer M, Stumpf TJ, Laurini L, Hoffmann A, Becker J, Miska A, Göttlich R, Herres‐Pawlis S, Schindler S. Kinetic Investigation of the Reaction of Dioxygen with the Copper(I) Complex [Cu(Pim
i
Pr2
)(CH
3
CN)]CF
3
SO
3
{Pim
i
Pr2
= Tris[2‐(1,4‐diisopropylimidazolyl)]phosphine}. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000462] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Markus Lerch
- Institut für Anorganische und Analytische Chemie Justus‐Liebig‐Universität Gießen Heinrich‐Buff‐Ring 17 35392 Gießen Germany
| | - Markus Weitzer
- Institut für Anorganische und Analytische Chemie Justus‐Liebig‐Universität Gießen Heinrich‐Buff‐Ring 17 35392 Gießen Germany
| | - Tim‐Daniel J. Stumpf
- Institut für Anorganische und Analytische Chemie Justus‐Liebig‐Universität Gießen Heinrich‐Buff‐Ring 17 35392 Gießen Germany
- Institut für Organische Chemie Justus‐Liebig‐Universität Gießen Heinrich‐Buff‐Ring 17 35392 Gießen Germany
| | - Larissa Laurini
- Institut für Anorganische Chemie RWTH Aachen University Landoltweg 1A 52074 Aachen Germany
| | - Alexander Hoffmann
- Institut für Anorganische Chemie RWTH Aachen University Landoltweg 1A 52074 Aachen Germany
| | - Jonathan Becker
- Institut für Anorganische und Analytische Chemie Justus‐Liebig‐Universität Gießen Heinrich‐Buff‐Ring 17 35392 Gießen Germany
| | - Andreas Miska
- Institut für Anorganische und Analytische Chemie Justus‐Liebig‐Universität Gießen Heinrich‐Buff‐Ring 17 35392 Gießen Germany
| | - Richard Göttlich
- Institut für Organische Chemie Justus‐Liebig‐Universität Gießen Heinrich‐Buff‐Ring 17 35392 Gießen Germany
| | - Sonja Herres‐Pawlis
- Institut für Anorganische Chemie RWTH Aachen University Landoltweg 1A 52074 Aachen Germany
| | - Siegfried Schindler
- Institut für Anorganische und Analytische Chemie Justus‐Liebig‐Universität Gießen Heinrich‐Buff‐Ring 17 35392 Gießen Germany
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