dc.contributor |
Nicolas Monsour, Nagi |
dc.contributor.author |
Jiménez Miró, José Ángel |
dc.date |
2011 |
dc.identifier.uri |
http://hdl.handle.net/2099.1/18060 |
dc.language.iso |
eng |
dc.publisher |
Universitat Politècnica de Catalunya |
dc.publisher |
Insitut Supérieur de l'Aéronautique et de l'Espace |
dc.rights |
info:eu-repo/semantics/openAccess |
dc.subject |
Àrees temàtiques de la UPC::Aeronàutica i espai::Aerodinàmica::Tunels aerodinàmics |
dc.subject |
Àrees temàtiques de la UPC::Aeronàutica i espai::Astronàutica::Enginyeria aeroespacial |
dc.subject |
Àrees temàtiques de la UPC::Física::Termodinàmica::Física de la transmissió de la calor |
dc.subject |
Space vehicles -- Thermodynamics |
dc.subject |
Space vehicles -- Atmospheric entry |
dc.subject |
Aerodynamic heating |
dc.subject |
Aerothermodynamics |
dc.subject |
Enthalpy |
dc.subject |
Plasma (Ionized gases) |
dc.subject |
Wind tunnels |
dc.subject |
Multiphysics modeling |
dc.subject |
Heat -- Transmission |
dc.subject |
Vehicles espacials -- Termodinàmica |
dc.subject |
Vehicles espacials -- Entrada atmosfèrica |
dc.subject |
Escalfament aerodinàmic |
dc.subject |
Aerotermodinàmica |
dc.subject |
Entalpia |
dc.subject |
Plasma (Gasos ionitzats) |
dc.subject |
Túnels aerodinàmics |
dc.subject |
Modelització multifísica |
dc.subject |
Calor -- Transmissió |
dc.title |
Simulations of high-enthalpy gases in an Electric Arc Heater – Study of Equilibrium vs. Non- Equilibrium assumptions and Uncertainty Quantifications of an Arc Jet |
dc.type |
info:eu-repo/semantics/bachelorThesis |
dc.description.abstract |
Space exploration has experienced exceptional advances the last years since the NASA’s
Apollo missions landed man on the moon. In spite of all the discoveries and advances in
computational power, the heat flux on the surface of atmospheric entry vehicles remains
as a high risk problem that has to be studied in a detailed manner. In order to avoid
possible inaccuracies in the calculation of the heat flux, it is of vital importance to understand
complex multiphysics phenomena that combine the chemical aspect of both the
materials and the hypersonic flows.
Since the man has stepped into space, the space vehicles that have been developed are
commonly exposed to tremendous aerodynamic heating, requiring an accurate study of
thermal protection systems (TPS). In order to test and understand the material response,
ground test facilities for the study of TPS have been developed. The most useful facilities
are plasma wind tunnels being able to provide high enthalpy flow for a long period.
The NASA Ames Research Center (ARC) Jet Complex segmented arc heater capabilities,
where plasma flows with high chemical purity are generated, will be reviewed. In these
tunnels, gas (typically air) is heated directly by a continuous electrical arc between two
sets of electrodes. Large amount of energy is transferred from electric to gas enthalpy
by making the gas conductive. The high-enthalpy gas generated in the constrictor passes
through a converging/diverging nozzle thus achieving high Mach number speeds. The
gases exit the nozzle into large vacuum chamber test sections. Flows in these facilities
produce a close approximation of the surface temperature, pressure and gas enthalpy
found in high velocity, hypersonic flows experienced by vehicles during atmospheric entry.
While the consideration of chemical equilibrium or not along the nozzle has been investigated
recently, the state of the gas in the constrictor has not been studied and will be a
subject of this project.
The operations of the 20 to 60 MW Arc Jet tunnels are expensive and do not lend
themselves to detailed scientific investigations. Recently, a mini Arc Jet test capability,
mARC, is being developed at ARC. This laboratory capability will enable fundamental
studies and can be instrumented for extracted fundamental quantities that will enable
better understanding of Arc Jet performance. In this work we simulate the mARC facility
and investigate the flow in the constrictor and through the nozzle. There are many
experimental uncertainties that may affect the heat flux at the test article placed in the
facility. In order to quantify the margins and reduce the uncertainties, Uncertainty Quantification
(UQ) methods will be used to define these margins. Sources of uncertainties can
be of different origins. Some of them are always present and are inherent to nature itself,
so they cannot be eliminated and are irreducible. Others, are just matter of the lack of
knowledge and are reducible. UQ techniques will permit to build a sensitivity analysis
which will allow us to determine the influence of experimental variables on the expected
output heat load. |
dc.description.abstract |
Outgoing |