Reitter, Louis Maximilian (2023)
Ice Particle Impact Onto Dry, Wet and Granular Substrates.
Technische Universität Darmstadt
doi: 10.26083/tuprints-00024752
Dissertation, Erstveröffentlichung, Verlagsversion
Kurzbeschreibung (Abstract)
Icing of turbofan aircraft engines can occur when aircraft fly through atmospheric conditions with large concentrations of ice crystals. Under such conditions, ice accumulations of substantial thickness can develop inside the engine, causing a blockage of the flow path and reducing engine power. When shedding, the ice accretions impact the downstream engine parts, causing damage and possibly a complete engine shutdown, threatening flight airworthiness and safety. Manufacturers are highly interested in robust numerical tools to predict engine icing. However, various fundamental processes involved in ice crystal icing are not yet completely understood, and thus, the existing numerical tools lack accuracy. The present work is devoted to advancing the understanding of particle impact processes relevant to ice crystal icing. For three topics, separate experimental setups and methodologies are developed, allowing investigation of the involved physical phenomena beyond the state of the art. Experimental investigations include the impact and fragmentation process of spherical ice particles. A small amount of residual ice fragments adheres to the impact target, which is quantified precisely for the first time. Employing an existing hydrodynamic model, characteristic length scales are proposed to estimate the adhering residual ice mass for sub-freezing target temperatures. Moreover, the size distribution of the fragment cloud is studied, which is of vital importance for several processes involved in engine icing. The obtained distributions are fitted with a power law, enabling a comparison with numerical simulations of generic brittle fracture and ice fracture processes observed on large scales. Furthermore, the ice particle impact onto wetted walls is investigated, focusing on the amount of energy dissipated during the collision. Existing models are modified and combined, explaining the observed low particle rebound velocity with a large dissipation during the plastic deformation of an ice particle. A dynamic strength measurement methodology is designed to investigate the material properties of ice accretions. Ice layers generated in a wind tunnel are studied and compared to artificial ice layers of various compositions generated in a laboratory environment. With the gained knowledge, ice layers with a realistic strength can be generated in the laboratory, enabling dedicated studies on ice layer erosion in the future. In summary, the present work contributes to a deeper understanding of ice particle impact phenomena relevant to aircraft engine icing, which may finally help to improve the accuracy of comprehensive numerical tools.
Typ des Eintrags: | Dissertation | ||||
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Erschienen: | 2023 | ||||
Autor(en): | Reitter, Louis Maximilian | ||||
Art des Eintrags: | Erstveröffentlichung | ||||
Titel: | Ice Particle Impact Onto Dry, Wet and Granular Substrates | ||||
Sprache: | Englisch | ||||
Referenten: | Hussong, Prof. Dr. Jeanette ; Roisman, Apl. Prof. Ilia V. ; Gillespie, Prof. David | ||||
Publikationsjahr: | 12 Dezember 2023 | ||||
Ort: | Darmstadt | ||||
Kollation: | xxxi, 160 Seiten | ||||
Datum der mündlichen Prüfung: | 28 Juni 2023 | ||||
DOI: | 10.26083/tuprints-00024752 | ||||
URL / URN: | https://tuprints.ulb.tu-darmstadt.de/24752 | ||||
Kurzbeschreibung (Abstract): | Icing of turbofan aircraft engines can occur when aircraft fly through atmospheric conditions with large concentrations of ice crystals. Under such conditions, ice accumulations of substantial thickness can develop inside the engine, causing a blockage of the flow path and reducing engine power. When shedding, the ice accretions impact the downstream engine parts, causing damage and possibly a complete engine shutdown, threatening flight airworthiness and safety. Manufacturers are highly interested in robust numerical tools to predict engine icing. However, various fundamental processes involved in ice crystal icing are not yet completely understood, and thus, the existing numerical tools lack accuracy. The present work is devoted to advancing the understanding of particle impact processes relevant to ice crystal icing. For three topics, separate experimental setups and methodologies are developed, allowing investigation of the involved physical phenomena beyond the state of the art. Experimental investigations include the impact and fragmentation process of spherical ice particles. A small amount of residual ice fragments adheres to the impact target, which is quantified precisely for the first time. Employing an existing hydrodynamic model, characteristic length scales are proposed to estimate the adhering residual ice mass for sub-freezing target temperatures. Moreover, the size distribution of the fragment cloud is studied, which is of vital importance for several processes involved in engine icing. The obtained distributions are fitted with a power law, enabling a comparison with numerical simulations of generic brittle fracture and ice fracture processes observed on large scales. Furthermore, the ice particle impact onto wetted walls is investigated, focusing on the amount of energy dissipated during the collision. Existing models are modified and combined, explaining the observed low particle rebound velocity with a large dissipation during the plastic deformation of an ice particle. A dynamic strength measurement methodology is designed to investigate the material properties of ice accretions. Ice layers generated in a wind tunnel are studied and compared to artificial ice layers of various compositions generated in a laboratory environment. With the gained knowledge, ice layers with a realistic strength can be generated in the laboratory, enabling dedicated studies on ice layer erosion in the future. In summary, the present work contributes to a deeper understanding of ice particle impact phenomena relevant to aircraft engine icing, which may finally help to improve the accuracy of comprehensive numerical tools. |
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Status: | Verlagsversion | ||||
URN: | urn:nbn:de:tuda-tuprints-247525 | ||||
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 Strömungslehre und Aerodynamik (SLA) |
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Hinterlegungsdatum: | 12 Dez 2023 13:19 | ||||
Letzte Änderung: | 13 Dez 2023 06:10 | ||||
PPN: | |||||
Referenten: | Hussong, Prof. Dr. Jeanette ; Roisman, Apl. Prof. Ilia V. ; Gillespie, Prof. David | ||||
Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 28 Juni 2023 | ||||
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