Pesci, Chiara (2019)
Computational Analysis of Fluid Interfaces Influenced by Soluble Surfactant.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
This work presents novel insights about the influence of soluble surfactants on rising bubbles obtained by direct numerical simulation (DNS). Surfactants are amphiphilic compounds which accumulate at fluid interfaces and significantly modify the respective interfacial properties, influencing also the overall dynamics of the flow. Since these interfaces are moving, continuously deforming and expanding, the local time-dependent interfacial coverage is the most relevant quantity. With the aid of DNS, local quantities, like the surfactant distribution on the bubble surface, can be accessed for a better understanding of the physical phenomena occurring close to the interface. However, the description and the simulation of such processes poses severe challenges. The core part of the physical model consists of the description of the surfactant transport in the bulk and on the deformable interface. The solution procedure is based on an arbitrary Lagrangian–Eulerian (ALE) interface-tracking method. The existing framework was enhanced to describe a wider range of physical phenomena. After a thorough validation of the latest numerical developments, the DNS of single rising bubbles in contaminated solutions is compared to experimental results. The full velocity transients of the rising bubbles, especially the contaminated ones, are correctly reproduced by the DNS. The simulation results are then studied to gain a better understanding of the local bubble dynamics under the effect of soluble surfactant. As an outlook, the mathematical and numerical models have been further extended to describe the influence of surfactant on the mass transfer from the bubble to the liquid phase. Two different models are studied; the first where the species and the surfactant transport are solved independently, and the second one where the hindrance effect of surfactant on mass transfer is taken into account. Preliminary simulation results are presented and discussed.
Typ des Eintrags: | Dissertation | ||||
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Erschienen: | 2019 | ||||
Autor(en): | Pesci, Chiara | ||||
Art des Eintrags: | Erstveröffentlichung | ||||
Titel: | Computational Analysis of Fluid Interfaces Influenced by Soluble Surfactant | ||||
Sprache: | Englisch | ||||
Referenten: | Bothe, Prof. Dr. Dieter ; Oberlack, Prof. Dr. Martin | ||||
Publikationsjahr: | 9 Juli 2019 | ||||
Ort: | Darmstadt | ||||
Datum der mündlichen Prüfung: | 9 Juli 2019 | ||||
URL / URN: | https://tuprints.ulb.tu-darmstadt.de/9303 | ||||
Kurzbeschreibung (Abstract): | This work presents novel insights about the influence of soluble surfactants on rising bubbles obtained by direct numerical simulation (DNS). Surfactants are amphiphilic compounds which accumulate at fluid interfaces and significantly modify the respective interfacial properties, influencing also the overall dynamics of the flow. Since these interfaces are moving, continuously deforming and expanding, the local time-dependent interfacial coverage is the most relevant quantity. With the aid of DNS, local quantities, like the surfactant distribution on the bubble surface, can be accessed for a better understanding of the physical phenomena occurring close to the interface. However, the description and the simulation of such processes poses severe challenges. The core part of the physical model consists of the description of the surfactant transport in the bulk and on the deformable interface. The solution procedure is based on an arbitrary Lagrangian–Eulerian (ALE) interface-tracking method. The existing framework was enhanced to describe a wider range of physical phenomena. After a thorough validation of the latest numerical developments, the DNS of single rising bubbles in contaminated solutions is compared to experimental results. The full velocity transients of the rising bubbles, especially the contaminated ones, are correctly reproduced by the DNS. The simulation results are then studied to gain a better understanding of the local bubble dynamics under the effect of soluble surfactant. As an outlook, the mathematical and numerical models have been further extended to describe the influence of surfactant on the mass transfer from the bubble to the liquid phase. Two different models are studied; the first where the species and the surfactant transport are solved independently, and the second one where the hindrance effect of surfactant on mass transfer is taken into account. Preliminary simulation results are presented and discussed. |
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Alternatives oder übersetztes Abstract: |
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URN: | urn:nbn:de:tuda-tuprints-93032 | ||||
Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau | ||||
Fachbereich(e)/-gebiet(e): | 16 Fachbereich Maschinenbau 16 Fachbereich Maschinenbau > Fachgebiet für Strömungsdynamik (fdy) |
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Hinterlegungsdatum: | 24 Nov 2019 20:55 | ||||
Letzte Änderung: | 24 Nov 2019 20:55 | ||||
PPN: | |||||
Referenten: | Bothe, Prof. Dr. Dieter ; Oberlack, Prof. Dr. Martin | ||||
Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 9 Juli 2019 | ||||
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