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Tesi etd-03282011-150958


Tipo di tesi
Tesi di laurea specialistica
Autore
ALLEGRA, GIUSEPPE
Indirizzo email
giuseppe.allegra@email.it
URN
etd-03282011-150958
Titolo
Stadi superiori criogenici di lanciatori: Design e aspetti di sviluppo tecnologico per schermatura termica innovativa
Struttura
INGEGNERIA
Corso di studi
INGEGNERIA AEROSPAZIALE
Commissione
relatore Prof. Frediani, Aldo
relatore Ing. Nebiolo, Marco
Parole chiave
  • Thermal Shield
  • ESA Launcher
  • Cryogenic Propulsion
  • Sandwich Panels
  • Boil-off
  • HyperWorks
  • Nastran
Data inizio appello
19/04/2011;
Disponibilità
completa
Riassunto analitico
The space business is changing: at beginning it was characterized by huge budgets justified by geopolitical reasons; today it is going through a phase of international cooperation characterized by budgets shrinking and by public opinion involvement decreasing.
The imminent dismission of the Space Shuttle Programme, the economic crisis, the presence of emerging countries interested in the space exploitation, have changed the approach to the space development. Today’s approach is towards an efficiency increasing of the already known technologies, instead to the development of new and more challenging technologies.
In this frame, the European Space Agency (ESA) is aiming to improving its launching capability; the strategy is focused both on technology amelioration, both in the creation of a more versatile launcher fleet.
The activity performed in this master’s degree thesis, in collaboration with TAS-I engineers, concerns on the improving of the cryogenic propulsion. Starting from a State of The Art (SoTA) review on launchers and engines, the study deal with a preliminary geometry study, equipped by analyses and sizing, of an LH2/LOX tank. The designed cryogenic tank has been assumed as basis to a deeper study on the main thesis object: the design and analysis of a Thermal Shield for Cryogenic Tank.
The various phases of launcher mission, in general, could be summarized in three main phases: On-Ground, Ascent and Cruise phases; in all three main phases it is very important to reduce the thermal gap between tank and external environment, to reduce degrading processes like the propellant boil-off.
For each phase have been identified the optimum countermeasures, based on the relative thermal transmission mechanism:
• On-Ground the predominant effect is the convection
• During the Ascent the atmospheric drug is the main thermal source
• During Cruising phase the thermal exchange is due to radiation.
ESA aims is to develop a system capable of ensuring thermal insulation on all the three phases, capable to be easily adapted to ESA next generation launcher, with a small total launcher mass increasing.
The system proposed by TAS-I, to fulfil the ESA request, is composed by a Multi-Layer Insulation (MLI) system wrapped over the thank (for Cruising phase), protected by a structural panel system (for Ascent phase) from the atmospheric drug; to reduce the boil-off On-Ground a Nitrogen at 77 K purging inside the Panel-MLI inter-space is foreseen. To reduce the panel additional mass, a jettisoning mechanism is designed to eject the structural panels at the beginnings of the Cruising phase.
To fulfil ESA stringent requirements, have been designed a Thermal Structure Panel using a sandwich configuration, assembled in geometry capable to sustain the structural loads, but at the same time, allowing the ejection.
The initial design, composed by 12 panels, has been discarded after the first analyses, and then other solution has been considered through a step by step optimization process to a final 6 panel architecture. The final panel will be realized and tested in order to reach a Technology Readiness Level of 6, as requested by ESA.
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