Kuhnhenn, Maximilian (2019)
Rotary Atomizer: Investigation of the Internal and External Liquid Flow and Atomization.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
Rotary atomizers are the preferred instrument of drying of many materials such as dairy products, foods, pharmaceuticals, polymers, etc. and are therefore often used in spray drying applications in the chemical and food industry. They are able to atomize complex, highly viscous, multicomponent liquids. Rotary atomizers have been successfully used in the spray drying industry for over 90 years, but increasing awareness for environmental concerns leads to the request for a higher energy efficiency. Based on the initial idea to improve the state-of-the-art design of rotary atomizers, this study tries to deliver an extensive insight into the underlying functional principle of rotary atomizers. Understanding and controlling the resultant droplet size distribution is crucial for the design process of spray dryers, since it is instrumental in determining the resultant powder size distribution.
In this thesis the internal flow inside a rotary atomizer, the mechanisms of primary atomization, the outer flow of the jets, rivulets and drops are studied experimentally and analyzed theoretically. The flow is observed using a high resolution video system, while the size, velocity vector and the number density of the drops in the spray are characterized using a phase Doppler measurement system.
Two main regions of the internal flow in the insert are identified: a thin film flow and a single rivulet flow. Correspondingly, the drops in the spray are formed as a result of the film and rivulet atomization processes.
Finally it is shown, that the average dimensionless drop diameter, scaled by the jet thickness, correlates very well with the dimensionless stretching parameter. A semi-empirical model for the average diameter of drops in the spray is developed.
| Typ des Eintrags: | Dissertation | ||||
|---|---|---|---|---|---|
| Erschienen: | 2019 | ||||
| Autor(en): | Kuhnhenn, Maximilian | ||||
| Art des Eintrags: | Erstveröffentlichung | ||||
| Titel: | Rotary Atomizer: Investigation of the Internal and External Liquid Flow and Atomization | ||||
| Sprache: | Englisch | ||||
| Referenten: | Tropea, Prof. Dr. Cameron ; Roisman, Prof. Dr. Ilia V. ; Walzel, Prof. Dr. Peter | ||||
| Publikationsjahr: | 4 Januar 2019 | ||||
| Ort: | Darmstadt | ||||
| Datum der mündlichen Prüfung: | 9 Oktober 2018 | ||||
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/7414 | ||||
| Kurzbeschreibung (Abstract): | Rotary atomizers are the preferred instrument of drying of many materials such as dairy products, foods, pharmaceuticals, polymers, etc. and are therefore often used in spray drying applications in the chemical and food industry. They are able to atomize complex, highly viscous, multicomponent liquids. Rotary atomizers have been successfully used in the spray drying industry for over 90 years, but increasing awareness for environmental concerns leads to the request for a higher energy efficiency. Based on the initial idea to improve the state-of-the-art design of rotary atomizers, this study tries to deliver an extensive insight into the underlying functional principle of rotary atomizers. Understanding and controlling the resultant droplet size distribution is crucial for the design process of spray dryers, since it is instrumental in determining the resultant powder size distribution. In this thesis the internal flow inside a rotary atomizer, the mechanisms of primary atomization, the outer flow of the jets, rivulets and drops are studied experimentally and analyzed theoretically. The flow is observed using a high resolution video system, while the size, velocity vector and the number density of the drops in the spray are characterized using a phase Doppler measurement system. Two main regions of the internal flow in the insert are identified: a thin film flow and a single rivulet flow. Correspondingly, the drops in the spray are formed as a result of the film and rivulet atomization processes. Finally it is shown, that the average dimensionless drop diameter, scaled by the jet thickness, correlates very well with the dimensionless stretching parameter. A semi-empirical model for the average diameter of drops in the spray is developed. |
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| Alternatives oder übersetztes Abstract: |
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| URN: | urn:nbn:de:tuda-tuprints-74148 | ||||
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 600 Technik, Medizin, angewandte Wissenschaften > 600 Technik 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften und Maschinenbau |
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| Fachbereich(e)/-gebiet(e): | 16 Fachbereich Maschinenbau 16 Fachbereich Maschinenbau > Fachgebiet Strömungslehre und Aerodynamik (SLA) 16 Fachbereich Maschinenbau > Fachgebiet Strömungslehre und Aerodynamik (SLA) > Tropfendynamik und Sprays |
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| Hinterlegungsdatum: | 03 Mär 2019 20:55 | ||||
| Letzte Änderung: | 03 Mär 2019 20:55 | ||||
| PPN: | |||||
| Referenten: | Tropea, Prof. Dr. Cameron ; Roisman, Prof. Dr. Ilia V. ; Walzel, Prof. Dr. Peter | ||||
| Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 9 Oktober 2018 | ||||
| Export: | |||||
| Suche nach Titel in: | TUfind oder in Google | ||||
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